GitLab

Update strings according to new guidance from UX.

Also added clearer descriptions to certain strings for easier
translations.

Bug: 1059607
Change-Id: I5e28e52e32c2dd97f75a50c396779db363202ef8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2341835Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Gavin Williams <gavinwill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796625}