Add "short words" for word based movements

[ModProg]

Currently helix has regular words e.g. move_next_word_end/e and long words move_next_long_word_end/`E´. I'd like to propose "short words", i.e. parts of words that are e.g. camelCase or snake_case.

The behavior I'd expect for the short word movement compared to regular and long (| is the current cursor position):

th|isIsAWord-otherWord separateLongWord

1. move_next_short_word_end: this|IsAWord-otherWord separateLongWord
2. move_next_word_end: thisIsAWord|-otherWord separateLongWord
3. move_next_long_word_end: thisIsAWord-otherWord| separateLongWord

This would be useful when e.g. changing parts of a test function name you pasted.

I'm unsure if there is a good default keymap to give this if any, would have proposed something like A-e but that is already occupied. This could also be a binding that is up to the user to assign.

[kirawi]

#8147

[ModProg]

Thanks, for some reason I was really convinced on short being the right word :D