Strip ~ and @ from modifiers before matching them

[TTWNO]

Had an issue where a keycombo like ~control + left was registering as just the left key without modifiers. This makes sure to strip any tildes or at signs before matching the modifier to the table.

[ajanon]

Thanks for your contribution!

If I understand this properly, this avoids trying to match ~control instead of control as a modifier key?

[TTWNO]

Yep, that's right!

[TTWNO]

Polite poke

[Shinyzenith]

@ajanon since I'm not well versed with the parser, would you like to merge? The code looks fine to me.