Auto merge of rust-lang#98914 - fee1-dead-contrib:min-deref-patterns, r=compiler-errors

Minimal implementation of implicit deref patterns for Strings

cc `@compiler-errors` `@BoxyUwU` rust-lang/lang-team#88 rust-lang#87121

~~I forgot to add a feature gate, will do so in a minute~~ Done

Author: bors

alloc/src/string.rs

@@ -362,8 +362,8 @@ use crate::vec::Vec;
 /// [`Deref`]: core::ops::Deref "ops::Deref"
 /// [`as_str()`]: String::as_str
 #[derive(PartialOrd, Eq, Ord)]
-#[cfg_attr(not(test), rustc_diagnostic_item = "String")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(all(not(bootstrap), not(test)), lang = "String")]
 pub struct String {
     vec: Vec<u8>,
 }