Implement parser sync idea to give multiple parse error when possible

[DenialAdams]

https://c3.handmade.network/blog/p/8632-handling_parsing_and_semantic_errors_in_a_compiler

Importantly, this is conservative so we went report errors that are not real

[DenialAdams]

Implemented in 1bd6146dc77b957ada6ab29fc010136af267cf43, although we could always try to do more