Rollup merge of #100483 - compiler-errors:point-to-projection-too, r=jyn514

Point to generic or arg if it's the self type of unsatisfied projection predicate

We do this for `TraitPredicate`s in `point_at_type_arg_instead_of_call_if_possible` and `point_at_arg_instead_of_call_if_possible`, so also do it for `ProjectionPredicate`.

Improves spans for a lot of unit tests.

diff --cc compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
Simple merge