Expose isTypeRelatedTo in the compiler API

[SamPruden]

I'm writing a transformer that needs to be able to evaluate type identity and assignability. I believe this is currently not possible with the compiler API. From what I can tell this could be enabled easily and harmlessly by exposing the isTypeRelatedTo function and providing an enum for the relation.

[DanielRosenwasser]

A PR is actually out for exactly this (#9943). Sounds like this is a duplicate of #9879.

[SamPruden]

Oh that's cool, sorry I missed the dupe. Any idea why it's gone so long unmerged? Is this unlikely to materialise any time soon?

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.