SUBMITTING_PATCHES: link to commit message style docs

Change-Id: I2090ebc43fc1c816b941a53dd89dbedf7bc61289
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/323696
Tested-by: Mike Frysinger <[email protected]>
Reviewed-by: Jack Neus <[email protected]>

Author: vapier

SUBMITTING_PATCHES.md

@@ -3,7 +3,7 @@
 # Short Version
 
  - Make small logical changes.
- - Provide a meaningful commit message.
+ - [Provide a meaningful commit message][commit-message-style].
  - Check for coding errors and style nits with flake8.
  - Make sure all code is under the Apache License, 2.0.
  - Publish your changes for review.
@@ -26,10 +26,11 @@ yourself with the following relevant bits.
 
 ## Make separate commits for logically separate changes.
 
-Unless your patch is really trivial, you should not be sending
-out a patch that was generated between your working tree and your
-commit head.  Instead, always make a commit with complete commit
-message and generate a series of patches from your repository.
+Unless your patch is really trivial, you should not be sending out a patch that
+was generated between your working tree and your commit head.
+Instead, always make a commit with a complete
+[commit message][commit-message-style] and generate a series of patches from
+your repository.
 It is a good discipline.
 
 Describe the technical detail of the change(s).
@@ -171,3 +172,6 @@ After you receive a Code-Review+2 from the maintainer, select the Verified
 button on the gerrit page for the change. This verifies that you have tested
 your changes and notifies the maintainer that they are ready to be submitted.
 The maintainer will then submit your changes to the repository.
+
+
+[commit-message-style]: https://chris.beams.io/posts/git-commit/