Inclusion of the parser refactor in 8.12

Hello, I'd like to mention that it would be nice if this patch https://gitlab.haskell.org/ghc/ghc/-/merge_requests/2377 could be included in 8.12. Right now we have a few issues that Ormolu users have reported which stem from how Haddocks are parsed by GHC (e.g. that issue when a file starts with haddock it must have a module header). I originally planned to work on those myself, but today I discovered that Vlad is already working on it. Best, Mark