Merge branch 'jc/release-notes-entry-experiment'

Introduce an experimental protocol for contributors to propose the
topic description to be used in the "What's cooking" report, the
merge commit message for the topic, and in the release notes and
document it in the SubmittingPatches document.

* jc/release-notes-entry-experiment:
  SubmittingPatches: release-notes entry experiment

Author: gitster

Documentation/SubmittingPatches

@@ -459,6 +459,18 @@ an explanation of changes between each iteration can be kept in
 Git-notes and inserted automatically following the three-dash
 line via `git format-patch --notes`.
 
+[[the-topic-summary]]
+*This is EXPERIMENTAL*.
+
+When sending a topic, you can propose a one-paragraph summary that
+should appear in the "What's cooking" report when it is picked up to
+explain the topic.  If you choose to do so, please write a 2-5 line
+paragraph that will fit well in our release notes (see many bulleted
+entries in the Documentation/RelNotes/* files for examples), and make
+it the first paragraph of the cover letter.  For a single-patch
+series, use the space between the three-dash line and the diffstat, as
+described earlier.
+
 [[attachment]]
 Do not attach the patch as a MIME attachment, compressed or not.
 Do not let your e-mail client send quoted-printable.  Do not let