Add autoninja* to .gitattributes.
Add autoninja* to .gitattributes.

Bug: b/77176746
Change-Id: I8f027daa6f867d61f0a9124a6d22c512bf91f219
Reviewed-on: https://chromium-review.googlesource.com/c/1325267
Reviewed-by: Dirk Pranke <6693ee08b084bb2ffa767f664c99b689395e0e4b@chromium.org>
Commit-Queue: Yoshisato Yanagisawa <5d95c5c75e3d691d9c77888fff4498e04f8b7157@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools