Clarify autofix behaviour on branch pushes

Author: wolph

CONTRIBUTING.rst

@@ -168,7 +168,8 @@ Automatic formatting
 Pull requests apply Ruff fixes before the lint check. With the autofix.ci
 app installed for this repository, those fixes are committed to the pull
 request branch, including forks. Findings Ruff cannot fix still fail CI.
-Push builds check the committed files without applying fixes.
+The CI lint job checks committed files on pushes. The separate autofix.ci
+workflow also runs on pushes to develop and master and can commit fixes.
 
 Apply the same fixes locally with::