GitLab

Change the domain placeholder name to manager and adjust its description
and add screenshot to make it easier for the translators to understand
the usage of the text.

Strings that are constructed with this message already use the manager
rather than the domain.

Bug: b:172678338
Test: None
Change-Id: Ife33997d6acd0e2d51d4c7a70f9f401816dcaa33
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2635141Reviewed-by: Brian Malcolm <bmalcolm@chromium.org>
Commit-Queue: Jana Grill <janagrill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845200}