magit/magit — pull request #1166 by snogge (2014-01-24 16:30:23+00:00)
Title: magit-key-mode-update-group: Create a THING entry if it does not exist

`magit-key-mode-update-group' could not handle unknown
THINGs. Unfortunately one of the unknown things were `arguments'. This
fix allows to add any type of THING, but the key-collision detection
only works for `actions', `switches' and `arguments'.