Misc doc edits for release.

release_notes/voltha_2.12.rst
-----------------------------
  o Update version and URLs for kafka
  o Update version and URLs for olt

howto/release/tasks/index.rst
howto/release/tasks/golang_gofmt_syntax.rst
-------------------------------------------
  o Document std golang formatting with gofmt -s -e -w.
  o Document content with references (commit message, make lint)
    diff --git a/howto/release/tasks/index.rst b/

Include a few edits from gerrit id I6e9658c23f436f83d423f74e01b2966943d2fe08

Change-Id: I27ad46ddd6673a9e35e794b1d3e8bb0644e8260d
diff --git a/howto/release/tasks/golang_gofmt_syntax.rst b/howto/release/tasks/golang_gofmt_syntax.rst
index 0f6bb1e..c34e2de 100644
--- a/howto/release/tasks/golang_gofmt_syntax.rst
+++ b/howto/release/tasks/golang_gofmt_syntax.rst
@@ -6,9 +6,12 @@
 Use the gofmt command to reformat golang sources gathered outside the vendor/ directory.
 
 .. code-block:: shell-session
-   :caption:
+   :caption: Golang source formatting
 
+   % git clone ssh://gerrit.opencord.org:29418/voltha-lib-go.git
+   % cd voltha-lib-go
+
+   % make sterile
    % make golang-fmt
 
-   % cd mysandbox
    % find . ! -path './vendor/\*' -name '*.go' -print | xargs -n1 gofmt -s -e -w