Rollup merge of #83980 - pierwill:fix-compiler-librustc-names, r=davidtwco

Fix outdated crate names in compiler docs

Changes `librustc_X` to `rustc_X`, only in documentation comments.
Plain code comments are left unchanged.

compiler/rustc_parse/src/lexer/mod.rs

@@ -128,7 +128,7 @@ impl<'a> StringReader<'a> {
     }
 
     /// Turns simple `rustc_lexer::TokenKind` enum into a rich
-    /// `librustc_ast::TokenKind`. This turns strings into interned
+    /// `rustc_ast::TokenKind`. This turns strings into interned
     /// symbols and runs additional validation.
     fn cook_lexer_token(&self, token: rustc_lexer::TokenKind, start: BytePos) -> Option<TokenKind> {
         Some(match token {