Autocomplete Feature

[FastestMolasses]

Description

Adds the first iteration of the autocomplete feature.

Related Issues

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots

[dankinsoid]

@FastestMolasses hi! I forked from your branch and found a crash:
StyledRangeStore+Internals.swift line 44
_guts[_guts.index(after: index)] fails with out of bounds error

this check fixes:
let nextIndex = _guts.index(after: index)
guard nextIndex < _guts.endIndex else { return }

[FastestMolasses]

This might have been a bug that was fixed in a later commit. I'll merge main into this soon and check it out, this PR is currently on hold until the Language Server Installation PR gets merged.

[tom-ludwig]

Hey @FastestMolasses was the status on the PR? Is it still up for review?