Rollup merge of rust-lang#86717 - rylev:rename, r=nikomatsakis

Rename some Rust 2021 lints to better names

Based on conversation in rust-lang#85894.

Rename a bunch of Rust 2021 related lints:

Lints that are officially renamed because they are already in beta or stable:
* `disjoint_capture_migration` => `rust_2021_incompatible_closure_captures`
* `or_patterns_back_compat` => `rust_2021_incompatible_or_patterns`
* `non_fmt_panic` => `non_fmt_panics`

Lints that are renamed but don't require any back -compat work since they aren't yet in stable:
* `future_prelude_collision` => `rust_2021_prelude_collisions`
* `reserved_prefix` => `rust_2021_token_prefixes`

Lints that have been discussed but that I did not rename:
* ~`non_fmt_panic` and `bare_trait_object`: is making this plural worth the headache we might cause users?~
* `array_into_iter`: I'm unsure of a good name and whether bothering users with a name change is worth it.

r? `@nikomatsakis`

Author: JohnTitor

core/src/lib.rs

@@ -164,7 +164,8 @@
 #![feature(no_niche)] // rust-lang/rust#68303
 #![feature(no_coverage)] // rust-lang/rust#84605
 #![deny(unsafe_op_in_unsafe_fn)]
-#![deny(or_patterns_back_compat)]
+#![cfg_attr(bootstrap, deny(or_patterns_back_compat))]
+#![cfg_attr(not(bootstrap), deny(rust_2021_incompatible_or_patterns))]
 
 // allow using `core::` in intra-doc links
 #[allow(unused_extern_crates)]