fix: use strip-literal for more correct comments removal

[leo-buneev]

When applying unimport on huge codebase, I've encountered many issues when global identifiers were not detected.
Some of them were fixed in #58 , but after that fix I've found several more complicated cases, e.g.:

const url = `http://${ref()}`

"//" was detected as single-line comment, discarded rest of the line, and first "`" quote was left unclosed, which lead to discarding of entire code.

This is complex to fix via replacing regexes, because many combinations are possible depending on the order - `str` // comment vs `str // not comment`.

To fix it properly we probably need to parse the syntax tree, but if I understood correctly Vite doesn't want to do it for performance reasons. So I've written small "state machine" to correctly detect strings and comments regardless of nesting in in O(n) time.

[antfu]

Thanks for the effort on this. Rather than maintaining the complexity in the repo, I have switched to using https://github.com/antfu/strip-literal, a library that Vite is relying on to remove the comments internals.

[leo-buneev]

Yes, that's better, thanks

[pi0]

This is so nice with strip-literal but as an effect, I see we are now using acorn parser on code now. Using with rollup, it would be nice to find a way reusing parsed AST...