Multi line comments and strings break when you modify a line in the middle

[alexispurslane]

This can be solved using the font lock region extender hook, the issue is figuring out how to do this efficiently. If it applies even when we're not in a string, things can get extremely slow extremely quickly, bc then it'd extend the region to the end of the last string and beginning of the next, so we somehow need a way to identify lines that are inside a string even if they have no quotes in them, and only extend the region then. I intend to consult existing emacs modes for ideas on this front.