Add third_party/clang-format/script to .gitignore. Bug: chromium:1447924 Change-Id: Ic2450d8883c904fdd667f4a2d603d990e84c6049 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4570960 Auto-Submit: Joanna Wang <jojwang@chromium.org> Commit-Queue: Joanna Wang <jojwang@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>