magit/magit — pull request #900 by praet (2013-09-18 07:17:13+00:00)
Title: `magit-diff-with-mark': better prompt and completion

When prompting for a rev to diff the currently marked commit with,
report the latter, and default to the currently checked out branch
unless that *is* the marked commit.

Signed-off-by: Pieter Praet