[Clang-tidy] Mention readability-static-definition-in-anonymous-namespace in release notes

[alexfh]

LG

clang-tools-extra/trunk/docs/ReleaseNotes.rst

- New `readability-redundant-control-flow
   Looks for procedures (functions returning no value) with ``return`` statements
   at the end of the function.  Such `return` statements are redundant.
 
 - New `readability-redundant-string-init
   <http://clang.llvm.org/extra/clang-tidy/checks/readability-redundant-string-init.html>`_ check
 
   Finds unnecessary string initializations.
 
+- New `readability-static-definition-in-anonymous-namespace
+  <http://clang.llvm.org/extra/clang-tidy/checks/readability-static-definition-in-anonymous-namespace.html>`_ check
+
+  Finds static function and variable definitions in anonymous namespace.
+
 Fixed bugs:
 
 - Crash when running on compile database with relative source files paths.
 
 - Crash when running with the `-fdelayed-template-parsing` flag.
 
-- The ``modernize-use-override`` check: incorrect fix-its placement around
+- The `modernize-use-override` check: incorrect fix-its placement around
   ``__declspec`` and other attributes.
 
 Clang-tidy changes from 3.7 to 3.8
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The 3.8 release didn't include release notes for :program:`clang-tidy`. In the
 3.8 release many new checks have been added to :program:`clang-tidy`: