Show keyboard shortcut conflicts better

[askmeaboutlo0m]

It's a bit annoying to resolve keyboard shortcut conflicts because you have to search through the whole list to find the red entries yourself. There should be some kind of button or something that filters out conflicts. Ideally these should stay persistent while the shortcut dialog is open, so that the contents of the filtered list don't obliterate themselves the instant you resolve them.

It should also show conflicts between canvas shortcuts and global shortcuts, since the latter will always take precedence.