Add `linux_repo_snapshot` got `.gitignore` (#40802)

It keeps popping up in my project searches ... This prevents that. Not
like we are planning on editing that file again.

Release Notes:

- N/A *or* Added/Fixed/Improved ...
69025f3bf4Lukas Wirth committed on 10/21/2025, 3:31:40 PM· committed by GitHubparent981fa28
1 file changedLine totals unavailable