[SAOC 2023] dfmt rewrite - Weekly update #13

[Prajwal S N]

Hi all,

At the end of milestone 3, this week has been a mix of work on 
DMD and dfmt. I got three more passes implemented into dfmt, 
bringing us closer to hitting feature parity. On the DMD side, I 
worked the raw comments into the AST by using another hash table 
in the parsing stage to track symbols and their comments. As 
@rikkimax mentioned in the previous update, it would make sense 
to have this feature under a separate feature flag instead of 
`DMDLIB` since it's very specific to dfmt/other projects that 
will use the AST (D-Scanner maybe?). I should have the PR up in 
the next week, just need to clean up all the debug printfs and 
make sure everything's working as intended.