keybindings: fix shift bindings

Shift Key bindings only generate one parenleft/parenright.

The Shift Key bindings were generating two parenleft/parenright characters.

Changed parenleft/parentright to shift+0 and shift+9. The xcape README says
this is the way to do it.

Using parenleft and parenright may have been fine; it could be that I was making
the call to xcape twice.