Rollup merge of #140536 - zachs18:mapped-guard-filter-map, r=Amanieu

Rename `*Guard::try_map` to `filter_map`.

Rename `std::sync::*Guard::try_map` to `filter_map`.

1. Analogous to `std::cell::Ref(Mut)::filter_map`.
2. Doesn't imply `Try` genericizability.

r? `@Amanieu` (or other T-libs-api)

Tracking issue for `mapped_lock_guards`: rust-lang/rust#117108

Author: matthiaskrgr