Summary: When I create new repos, I always forget which is which (between Callsign and Short Name) This adds helpful text as a placeholder and as control instructions I am not sure if this layout is 100% better, but this is an option as well **Add new Repository** {F3169761 width=800} **Edit existing Repository** {F3169775 width=800} Closes T15742 Test Plan: Added a new repository and saw these control instructions Reviewers: O1 Blessed Committers, aklapper Reviewed By: O1 Blessed Committers, aklapper Subscribers: aklapper, avivey, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno Maniphest Tasks: T15742 Differential Revision: https://we.phorge.it/D25898