Add method of binding an ErrorCode to parser errors

[philberty]

we use an Error struct in rust-diagnostics.h

gccrs/gcc/rust/rust-diagnostics.h

Line 133 in 5406b63

struct Error

This does not have the ability to store an Error code or Rich location so we cannot emit error codes for parser errors or expansion errors

[philberty]

@MahadMuhammad ^^