Rollup merge of #103468 - chenyukang:yukang/fix-103435-extra-parentheses, r=estebank

Fix unused lint and parser caring about spaces to won't produce invalid code

Fixes #103435

compiler/rustc_parse/src/errors.rs

@@ -1165,10 +1165,12 @@ pub(crate) struct ParenthesesInForHead {
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(suggestion, applicability = "machine-applicable")]
 pub(crate) struct ParenthesesInForHeadSugg {
-    #[suggestion_part(code = "")]
+    #[suggestion_part(code = "{left_snippet}")]
     pub left: Span,
-    #[suggestion_part(code = "")]
+    pub left_snippet: String,
+    #[suggestion_part(code = "{right_snippet}")]
     pub right: Span,
+    pub right_snippet: String,
 }
 
 #[derive(Diagnostic)]