dinput: Clarify a translatable string

[Frédéric Delanoy]

2011/12/4 Lucas Zawacki <lfzawacki at gmail.com>:
> To be fair the idea IS categorization, as it doesn't matter if the
> buttons are sorted in a particular order between them. The original
> ConfigureDevices dialog is here
> http://msdn.microsoft.com/en-us/library/bb206296%28v=vs.85%29.aspx ,
> you can see the checkbox there. I think "Show assigned first" is
> better too.

Right, I'll use that in a reviewed patch, likely with a message
context indicating it pertains to mappings.
That should probably do it.

Frédéric