docs: fix syntax highlighting of code blocks

And various other cleanups

Change-Id: If945f5407036e73db980cafd2185359a488a0ff1
diff --git a/docs/release-notes/release-notes-0.6.1.rst b/docs/release-notes/release-notes-0.6.1.rst
index c1f5a4f..95a7dbb 100644
--- a/docs/release-notes/release-notes-0.6.1.rst
+++ b/docs/release-notes/release-notes-0.6.1.rst
@@ -3,8 +3,8 @@
 
 Release date: February 19, 2018
 
-New features:
-^^^^^^^^^^^^^
+New features
+^^^^^^^^^^^^
 
 - (potentially breaking change) :ndn-cxx:`expressInterest` now by default loopbacks Interests to
   producer callbacks on the same :ndn-cxx:`Face`.  When undesired, use