Update release notes

Author: gedare

clang/docs/ReleaseNotes.rst

@@ -703,6 +703,8 @@ clang-format
   multi-line comments without touching their contents, renames ``false`` to
   ``Never``, and ``true`` to ``Always``.
 - Adds ``RemoveEmptyLinesInUnwrappedLines`` option.
+- Adds ``AlignAfterOpenBracketBreak`` sub-options for better control of
+  ``AlignAfterOpenBracket`` with ``AlwaysBreak`` or ``BlockIndent`` modes.
 
 libclang
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