Rollup merge of #102977 - lukas-code:is-sorted-hrtb, r=m-ou-se

remove HRTB from `[T]::is_sorted_by{,_key}`

Changes the signature of `[T]::is_sorted_by{,_key}` to match `[T]::binary_search_by{,_key}` and make code like https://github.com/rust-lang/rust/issues/53485#issuecomment-885393452 compile.

Tracking issue: https://github.com/rust-lang/rust/issues/53485

~~Do we need an ACP for something like this?~~ Edit: Filed ACP here: https://github.com/rust-lang/libs-team/issues/121

diff --cc library/core/src/slice/mod.rs
Simple merge