[libc++] Add empty line in ReleaseNotes.rst

NOKEYCHECK=True
GitOrigin-RevId: deed2466315ecb269368ba5799e4bb17c619fcaf
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index ce13166..86a9bc0 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -57,6 +57,7 @@
   If, after updating libc++, you see compiler errors related to missing declarations in
   namespace ``std``, it might be because one of your source files now needs to
   ``#include <algorithm>`` and/or ``#include <chrono>``.
+
 ABI Changes
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