Fix documentation markdown syntax with lint rule

ref: https://github.com/markdownlint/markdownlint/blob/master/docs/RULES.md

Most of my modified are about following rules:

* MD001 Header levels should only increment by one level at a time
* MD009 Trailing spaces
* MD026 Trailing punctuation in header
* MD027 Multiple spaces after blockquote symbol
* MD031 Fenced code blocks should be surrounded by blank lines

and I change `prereqs/k8s-single-node.md`, `prereqs/k8s-multi-node.md`'s
`Done` to `Next Step`, because with trailling punctuation in header
offend MD026.

Change-Id: Ibe173518b972c02f990ffe8309fa87a8fcabb054
diff --git a/charts/voltha.md b/charts/voltha.md
index 539be82..1402dda 100644
--- a/charts/voltha.md
+++ b/charts/voltha.md
@@ -3,32 +3,37 @@
 ## First Time Installation
 
 Add the kubernetes helm charts incubator repository
+
 ```shell
 helm repo add incubator https://kubernetes-charts-incubator.storage.googleapis.com/
 ```
 
 Build dependencies
+
 ```shell
 helm dep build voltha
 ```
 
 There's an etcd-operator **known bug** we're trying to solve that
 prevents users to deploy Voltha straight since the first time. We
-found a workaround. 
+found a workaround.
 
 Few steps:
 
 Install Voltha (without etcd operator)
+
 ```shell
 helm install -n voltha --set etcd-operator.customResources.createEtcdClusterCRD=false voltha
 ```
 
 Uninstall Voltha
+
 ```shell
 helm delete --purge voltha
 ```
 
 Deploy Voltha
+
 ```shell
 helm install -n voltha voltha
 ```
diff --git a/navigate.md b/navigate.md
index ea73b69..4e2aced 100644
--- a/navigate.md
+++ b/navigate.md
@@ -1,4 +1,4 @@
-# Navigating CORD 
+# Navigating CORD
 
 The relationship between installing, operating, and developing
 CORD—and the corresponding toolsets and specification files
diff --git a/operating_cord/general.md b/operating_cord/general.md
index 154cb47..49a06ce 100644
--- a/operating_cord/general.md
+++ b/operating_cord/general.md
@@ -1,15 +1,15 @@
 # General Info
 
-CORD's operations and management interface is primarily defined by 
-its Northbound API. There is typically more than one variant of this 
-interface, and they are auto-generated from the models loaded into 
+CORD's operations and management interface is primarily defined by
+its Northbound API. There is typically more than one variant of this
+interface, and they are auto-generated from the models loaded into
 CORD, as described [elsewhere](../xos/README.md). Most notably:
 
 * A graphical interface is documented [here](gui.md).
 
-* A RESTful version of this API is documented [here](rest_apis.md). 
+* A RESTful version of this API is documented [here](rest_apis.md).
 
-* A TOSCA version is typically used to configure and provision a 
-   POD. Later sections of this guide give examples of TOSCA workflows 
+* A TOSCA version is typically used to configure and provision a
+   POD. Later sections of this guide give examples of TOSCA workflows
    used to provision and configure various [profiles](profiles.md)
    and [services](services.md).
diff --git a/overview.md b/overview.md
index 564dcaa..c6a67da 100644
--- a/overview.md
+++ b/overview.md
@@ -13,15 +13,15 @@
 
 The guide is organized around the major stages in the lifecycle of CORD:
 
-* [Installation](README.md): Installing (and later upgrading) CORD. 
-* [Operations](operating_cord/operating_cord.md): Operating an already 
-  installed CORD deployment. 
-* [Development](developer/developer.md): Developing new functionality 
-  to be included in CORD. 
-* [Testing](cord-tester/README.md): Testing functionality to be 
- included in CORD. 
+* [Installation](README.md): Installing (and later upgrading) CORD.
+* [Operations](operating_cord/operating_cord.md): Operating an already
+  installed CORD deployment.
+* [Development](developer/developer.md): Developing new functionality
+  to be included in CORD.
+* [Testing](cord-tester/README.md): Testing functionality to be
+ included in CORD.
 
-These are all fairly obvious. What's less obvious is the relationship among 
+These are all fairly obvious. What's less obvious is the relationship among
 these stages, which is helpful in [Navigating CORD](navigate.md).
 
 ## Making Changes to the Guide
diff --git a/partials/push-images-to-registry.md b/partials/push-images-to-registry.md
index 52a4612..cac2de6 100644
--- a/partials/push-images-to-registry.md
+++ b/partials/push-images-to-registry.md
@@ -4,26 +4,31 @@
 be first tagged, and pushed to the local registry:
 
 Supposing your docker-registry address is:
+
 ```shell
 192.168.0.1:30500
 ```
 
 and that your original image name is called:
+
 ```shell
 xosproject/vsg-synchronizer
 ```
 
 you'll need to tag the image as
+
 ```shell
 192.168.0.1:30500/xosproject/vsg-synchronizer
 ```
 
 For example, you can use the *docker tag* command to do this:
+
 ```shell
 docker tag xosproject/vsg-synchronizer:candidate 192.168.0.1:30500/xosproject/vsg-synchronizer:candidate
 ```
 
 Now, you can push the image to the registry. For example, with *docker push*:
+
 ```shell
 docker push 192.168.0.1:30500/xosproject/vsg-synchronizer:candidate
 ```
diff --git a/prereqs/README.md b/prereqs/README.md
index 9195069..a3fc2f4 100644
--- a/prereqs/README.md
+++ b/prereqs/README.md
@@ -7,6 +7,6 @@
 
 There are three categories of requirements that must be met before installing CORD:
 
-* [Hardware Requirements](hardware.md) 
-* [Connectivity Requirements](networking.md) 
-* [Software Requirements](software.md) 
+* [Hardware Requirements](hardware.md)
+* [Connectivity Requirements](networking.md)
+* [Software Requirements](software.md)
diff --git a/prereqs/helm.md b/prereqs/helm.md
index 9c8ded4..b3a6cd0 100644
--- a/prereqs/helm.md
+++ b/prereqs/helm.md
@@ -32,14 +32,14 @@
 helm init
 kubectl create serviceaccount --namespace kube-system tiller
 kubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tiller
-kubectl patch deploy --namespace kube-system tiller-deploy -p '{"spec":{"template":{"spec":{"serviceAccount":"tiller"}}}}'      
+kubectl patch deploy --namespace kube-system tiller-deploy -p '{"spec":{"template":{"spec":{"serviceAccount":"tiller"}}}}'
 helm init --service-account tiller --upgrade
 ```
 
 Once *helm* and *tiller* are installed you should be able to run the
 command *helm ls* without errors.
 
-## Done?
+## Next Step
 
 Once you are done, you are ready to deploy CORD components using their
 helm charts! See [Bringing Up CORD](../profiles/intro.md). For more detailed
diff --git a/prereqs/k8s-multi-node.md b/prereqs/k8s-multi-node.md
index c5c44fd..7b70562 100644
--- a/prereqs/k8s-multi-node.md
+++ b/prereqs/k8s-multi-node.md
@@ -30,6 +30,7 @@
 ## Download the Kubespray Installation Scripts
 
 On the operator machine
+
 ```shell
 git clone https://gerrit.opencord.org/automation-tools
 ```
@@ -74,6 +75,7 @@
 * Downloads and exports the access configuration outside the Kubespray folder, so it won’t be removed at the next execution of the script (for example while trying to re-deploy the POD, or while deploying a different POD)
 
 To run the installation script, type
+
 ```shell
 ./setup.sh -i onf 10.90.0.101 10.90.0.102 10.90.0.103
 ```
@@ -90,6 +92,7 @@
 
 If you want to deploy another POD without affecting your existing
 deployment run the following:
+
 ```shell
 ./setup.sh -i my_other_deployment 192.168.0.1 192.168.0.2 192.168.0.3
 ```
@@ -114,9 +117,9 @@
 
 At this point, you can start to use *kubectl*  and *helm*.
 
-## Done?
+## Next Step
 
-Once you are done, you are ready to install Kubctl and Helm, so return to 
+Once you are done, you are ready to install Kubctl and Helm, so return to
 [here](kubernetes.md#get-your-kubeconfig-file) in the installation
 guide.
 
diff --git a/prereqs/k8s-single-node.md b/prereqs/k8s-single-node.md
index ad08a06..9e3877c 100644
--- a/prereqs/k8s-single-node.md
+++ b/prereqs/k8s-single-node.md
@@ -15,7 +15,7 @@
     * Documentation: <https://microk8s.io/>
     * One machine, Linux based, either physical machine or virtual. It could also be your own PC!
 
-## Done?
+## Next Step
 
 Once you are done, you are ready to install Kubctl and Helm, so return to
 [here](kubernetes.md#get-your-kubeconfig-file) in the installation guide.
diff --git a/prereqs/software.md b/prereqs/software.md
index d8c00fe..03b0a07 100644
--- a/prereqs/software.md
+++ b/prereqs/software.md
@@ -7,8 +7,8 @@
 
 > **Note:** M-CORD is the exception since its components still depend on
 > OpenStack, which is in turn deployed as a set of Kubernetes containers
->using the [openstack-helm](https://github.com/openstack/openstack-helm)
->project. Successfully installing the OpenStack Helm charts requires
->some additional system configuration besides just installing Kubernetes
->and Helm. You can find more informations about this in the
->[OpenStack Support](./openstack-helm.md) installation section.
+> using the [openstack-helm](https://github.com/openstack/openstack-helm)
+> project. Successfully installing the OpenStack Helm charts requires
+> some additional system configuration besides just installing Kubernetes
+> and Helm. You can find more informations about this in the
+> [OpenStack Support](./openstack-helm.md) installation section.
diff --git a/profiles/mcord/configuration.md b/profiles/mcord/configuration.md
index 9e55602..6bdf4af 100644
--- a/profiles/mcord/configuration.md
+++ b/profiles/mcord/configuration.md
@@ -1,6 +1,6 @@
-# M-CORD Configuration 
+# M-CORD Configuration
 
 Once all the components needed for M-CORD are up and running on your POD,
-you'll need to configure XOS with the proper configuration. 
+you'll need to configure XOS with the proper configuration.
 Since this configuration is environment specific, you'll need to create your own,
 but the following can serve as a reference for it:
diff --git a/profiles/rcord/configuration.md b/profiles/rcord/configuration.md
index 097d1be..887f644 100644
--- a/profiles/rcord/configuration.md
+++ b/profiles/rcord/configuration.md
@@ -1,7 +1,7 @@
-# R-CORD Configuration 
+# R-CORD Configuration
 
 Once all the components needed for the R-CORD profile are up and
-running on your POD, you'll need to configure XOS with the proper configuration. 
+running on your POD, you'll need to configure XOS with the proper configuration.
 Since this configuration is environment specific, you'll need to create your own,
 but the following can serve as a reference for it:
 
@@ -126,7 +126,7 @@
 please refer to the [RCORD Service](../../rcord/README.md) guide for
 more informations.
 
-### Create a subscriber in RCORD
+## Create a subscriber in RCORD
 
 To create a subscriber in CORD you need to retrieve some informations:
 
@@ -159,6 +159,7 @@
 | 00015698e67dc060 | broadcom_onu | True | 0001941bd45e71d8 |     ENABLED |      ACTIVE |      REACHABLE |      536870912 |                  |      BRCM|        0001941bd45e71d8 |                    1 |                            1 |
 +------------------+--------------+------+------------------+-------------+-------------+----------------+----------------+------------------+----------+-------------------------+----------------------+------------------------------+
 ```
+
 to list all the existing devices, and locate the correct ONU, then:
 
 ```shell
@@ -193,6 +194,7 @@
 |                  flows.items |        5 item(s) |
 +------------------------------+------------------+
 ```
+
 to find the correct serial number.
 
 **Push a subscriber into CORD**
@@ -220,7 +222,7 @@
 
 _For instructions on how to push TOSCA, please refer to this [guide](../../xos-tosca/README.md)_
 
-### Zero-Touch Subscriber Provisioning
+## Zero-Touch Subscriber Provisioning
 
 This feature, also referred to as "bottom-up provisioning" enables auto-discovery
 of subscriber and their validation through an external OSS.
diff --git a/profiles/rcord/install.md b/profiles/rcord/install.md
index 1bcae02..c08c1cf 100644
--- a/profiles/rcord/install.md
+++ b/profiles/rcord/install.md
@@ -28,7 +28,7 @@
 helm install -n rcord-lite xos-profiles/rcord-lite
 ```
 
-Now that your R-CORD deployment is complete, please read this 
+Now that your R-CORD deployment is complete, please read this
 to understand how to configure it: [Configure R-CORD](configuration.md)
 
 ## Customizing an R-CORD Install