fix: use cannot have optional generics

Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

Author: winstxnhdw

src/tools/rust-analyzer/crates/syntax/rust.ungram

@@ -629,7 +629,7 @@ TypeBoundList =
 TypeBound =
   Lifetime
 | ('~' 'const' | 'const')? 'async'? '?'? Type
-| 'use' GenericParamList?
+| 'use' GenericParamList
 
 //************************//
 //        Patterns        //