Remove regex parser

[MischaPanch]

Hey. I don't want to discourage you or anything like that, and I get that lot's of things are possible with vibe-coding today.

Still, I would recommend you to remove the fast, regex based mode. It cannot work well in theory, programming languages are not regular languages. You will get issues on this, and no amount of patching the regexes will ever help.

Linking the legendary stackoverflow post on html (in those days nobody would have even considered parsing a proper language with regex)
https://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454