Split the lifetimes of MirBorrowckCtxt

[oli-obk]

These lifetimes are sometimes too general and will link things together that are independent. These are a blocker for actually finishing tracking more state (e.g. error tainting) in the diagnostic context handle, and I'd rather land it in its own PR instead of together with functional changes.

Also changes a bunch of named lifetimes to '_ where they were irrelevant

follow-up to #126623

[rustbot]

r? @cjgillot

rustbot has assigned @cjgillot.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[compiler-errors]

r=me when ci green

[compiler-errors]

@bors rollup

[compiler-errors]

@bors r+

[bors]

📌 Commit 8fc6b3d has been approved by compiler-errors

It is now in the queue for this repository.