Add an option to disable specific sequences

[aer0aa]

I think there should be an option to disable specific sequences. This would be useful if you wanted to add a sequence that starts with the other sequence e.g. Normally, if you wanted to make one that starts with l and t, you wouldn't be able to because of the shortcut for "<" unless you disable every sequence in the Xorg project, which also disables a lot of useful ones. If you could just disable that one, it'd be much more convenient