Migrate to more inclusive terminology.

Bug: 1097674
Change-Id: I387b385ff36c7766682c06af34ed5fc6115119d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2268403Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Ayu Ishii <ayui@chromium.org>