Code review comment for lp:~widelands-dev/widelands/critter_editor_categories

Thanks for testing! I will see about making the terrain menus the same width when I get home.

@topopple: while the explanation is looking awkward with the duck now, it is old code in a superclass for the terrain, immovables and animals tools. Implementing a ? button will mean quite a bit of new code, so I really don't want to do that in this branch - it will make this diff even bigger. So, time for a new bug ;)