refactor: Text formatting functions

[marcustyphoon]

Description

Should result in no functional changes. This extracts some utility functions that are used in the modals of various scripts into a utility file to reduce repetition.

Open to bikeshedding (different file name, interface.js, modals.js, whatever).

Testing steps

[marcustyphoon]

Spoken like a true developer-whose-project-at-work-uses-a-bundler, I kid, I kid, don't sue me, I'm innocent :P

I certainly don't think I would go unequivocally to the opposite extreme, where one winds up with a folder full of function names in alphabetical order. If a set of functions will usually be used together or would need all need to be refactored at the same time, I think it makes sense to be able to find one from the other via context. But yeah, I think there's certainly places for it. interface.js is pretty much a grab bag, iirc. I feel like it might make sense to put the functions that take an NPF object together (might have to add one to normalize community posts?)