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/code/linting.rst b/howto/code/linting.rst
index aaba632..b75b96a 100644
--- a/howto/code/linting.rst
+++ b/howto/code/linting.rst
@@ -277,7 +277,7 @@
 Sources:
 
 - `makefiles/lint <https://gerrit.opencord.org/plugins/gitiles/onf-make/+/refs/heads/master/makefiles/lint/>`__
-- `makefiles/lint/robot.mk <https://gerrit.opencord.org/plugins/gitiles/onf-make/+/refs/heads/master/makefiles/lint/robot.mk>`_
+- `makefiles/lint/robot/*.mk <https://gerrit.opencord.org/plugins/gitiles/onf-make/+/refs/heads/master/makefiles/lint/robot>`_
 
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