In nosquash mode, `git cl` is pretty challenging to use since we don't
have issue numbers. All three parts of the triplet id are readily
available though. This CL adds a fallback to `git cl` which looks up the
issue number by getting the change details by triplet_id.
Change-Id: I0839fe75bcb4bc8d60ff36b4da26dc0e419a1493
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5633186
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Reviewed-by: Gavin Mak <gavinmak@google.com>