Auto merge of #118655 - compiler-errors:rollup-vrngyzn, r=compiler-errors

Rollup of 9 pull requests

Successful merges:

 - #117793 (Update variable name to fix `unused_variables` warning)
 - #118123 (Add support for making lib features internal)
 - #118268 (Pretty print `Fn<(..., ...)>` trait refs with parentheses (almost) always)
 - #118346 (Add `deeply_normalize_for_diagnostics`, use it in coherence)
 - #118350 (Simplify Default for tuples)
 - #118450 (Use OnceCell in cell module documentation)
 - #118585 (Fix parser ICE when recovering `dyn`/`impl` after `for<...>`)
 - #118587 (Cleanup error handlers some more)
 - #118642 (bootstrap(builder.rs): Don't explicitly warn against `semicolon_in_expressions_from_macros`)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

crates/proc-macro-srv/src/lib.rs

@@ -13,7 +13,7 @@
 #![cfg(feature = "sysroot-abi")]
 #![feature(proc_macro_internals, proc_macro_diagnostic, proc_macro_span)]
 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
-#![allow(unreachable_pub)]
+#![allow(unreachable_pub, internal_features)]
 
 extern crate proc_macro;