rearrange my gitingore addition w/comment to make backporting easier (python#134945)

Author: gpshead

.gitignore

@@ -171,9 +171,10 @@ Python/frozen_modules/MANIFEST
 /python
 !/Python/
 
-# main branch only: ABI files are not checked/maintained.
-Doc/data/python*.abi
-
 # People's custom https://docs.anthropic.com/en/docs/claude-code/memory configs.
 /.claude/
 CLAUDE.local.md
+
+#### main branch only stuff below this line, things to backport go above. ####
+# main branch only: ABI files are not checked/maintained.
+Doc/data/python*.abi