Regarding rust-lang#50974: showing help message to remove comma

Author: PramodBisht

src/libsyntax/parse/parser.rs

@@ -767,6 +767,9 @@ impl<'a> Parser<'a> {
             err.span_label(self.span, format!("expected identifier, found {}", token_descr));
         } else {
             err.span_label(self.span, "expected identifier");
+            if self.token == token::Comma {
+                err.span_suggestion(self.span, "remove this comma", ",".into());
+            }
         }
         err
     }