bin/gen_release_notes: automatically commit release notes

Cc: mesa-stable
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5833>
diff --git a/bin/gen_release_notes.py b/bin/gen_release_notes.py
index c72e440..716f807 100755
--- a/bin/gen_release_notes.py
+++ b/bin/gen_release_notes.py
@@ -25,6 +25,7 @@
 import datetime
 import os
 import pathlib
+import subprocess
 import sys
 import textwrap
 import typing
@@ -252,6 +253,10 @@
         except:
             print(exceptions.text_error_template().render())
 
+    subprocess.run(['git', 'add', final])
+    subprocess.run(['git', 'commit', '-m',
+                    f'docs: add release notes for {this_version}'])
+
 
 if __name__ == "__main__":
     loop = asyncio.get_event_loop()
diff --git a/docs/releasing.rst b/docs/releasing.rst
index b7a4af3..529dcd6 100644
--- a/docs/releasing.rst
+++ b/docs/releasing.rst
@@ -262,7 +262,7 @@
 
 The release notes are completely generated by the
 ``bin/gen_release_notes.py`` script. Simply run this script before
-bumping the version, and commit the results. The only thing left to do
+bumping the version. The only thing left to do
 is add the sha256 sums.
 
 Increment the version contained in the file VERSION at Mesa's top-level,