Rewritelifetimes lint pass. This mainly reduces the amount of work done when no lint is produced, but has a few behavior changes.

* Input to output inference on `dyn Trait` lifetimes is handled with a sufficient MSRV.
* Elision on `dyn Trait` input lifetimes where the lifetime is used only once is suggested on all versions.
* Lifetimes that are only used as a constraint on a single type are no longer detected. This is a regression.
* A bunch of cases where the lints where prevented, but only a single lifetime was non-elidible now lint on remaining lifetimes.

Author: Jarcho

clippy_lints/src/lib.rs

@@ -9,6 +9,7 @@
 #![feature(never_type)]
 #![feature(round_char_boundary)]
 #![feature(rustc_private)]
+#![feature(slice_partition_dedup)]
 #![feature(stmt_expr_attributes)]
 #![feature(unwrap_infallible)]
 #![recursion_limit = "512"]