Previously, an anonymous type was used for creating a diagnostic with related
information. The anonymous type would then be translated into the necessary
`ts.DiagnosticRelatedInformation` shape within `makeDiagnostic`. This commit
switches the `makeDiagnostic` signature over to taking `ts.DiagnosticRelatedInformation`
directly and introduces `makeRelatedInformation` to easily create such objects.
This is done to aid in making upcoming work more readable.
PR Close#37587