fix: reexport Source, Range and DiagnosticMessage from compiler's index.d.ts

[willemneal]

This means any tool which imports the types from both, e.g. vistor-as there will be one source of truth.

[dcodeIO]

If I understood correctly, asc does indeed not expose all members of the internal classes in question, and I think that made it necessary to define a subset of only those properties actually present. Not sure if that applies to all of them, though.

Relevant PR: #1625
cc @piotr-oles

[piotr-oles]

Yes, these typings are a subset on purpose - we are exposing only a few fields. It's because the compiler can be compiled to WASM and if it runs in a WASM environment, then we have to copy these diagnostics. We could use the Pick<> type instead of duplicating them - but re-exporting them would create invalid expectations in some cases :)