Rollup merge of #141551 - compiler-errors:hir-lints, r=BoxyUwU

Make two transmute-related MIR lints into HIR lint

Make `PTR_TO_INTEGER_TRANSMUTE_IN_CONSTS` (rust-lang/rust#130540) and `UNNECESSARY_TRANSMUTES` (rust-lang/rust#136083) into "normal" HIR-based lints.

Funny enough this came up in the review of the latter (rust-lang/rust#136083 (comment)), but I guess it just was overlooked.

But anywyas, there's no reason for these to be MIR lints; in fact, it makes the suggestions for them a bit more complicated than necessary.

Note that there's probably a few more simplifications and improvements to be done here. Follow-ups can be done in a separate PR, especially if they're about the messaging and suggestions themselves, which I didn't write.

Author: tgross35