Make Git ignore .git_cl_description_backup
Make Git ignore .git_cl_description_backup

Change-Id: I7e8c422a3fef45499d43fdf21a17b72eccf6725d
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/1944332
Auto-Submit: Mathias Bynens <17a2cbc4e33156874a9862b0f530521117e66a3d@chromium.org>
Reviewed-by: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
Commit-Queue: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>

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