Remove unused features

compiler/rustc_mir_transform/src/lib.rs

@@ -14,11 +14,9 @@
 #![feature(never_type)]
 #![feature(option_get_or_insert_default)]
 #![feature(round_char_boundary)]
-#![feature(trusted_step)]
 #![feature(try_blocks)]
 #![feature(yeet_expr)]
 #![feature(if_let_guard)]
-#![recursion_limit = "256"]
 
 #[macro_use]
 extern crate tracing;