Fix unuseful fixme

Signed-off-by: xizheyin <[email protected]>

Author: xizheyin

compiler/rustc_parse/src/parser/mod.rs

@@ -919,7 +919,7 @@ impl<'a> Parser<'a> {
                                     // Parsed successfully, therefore most probably the code only
                                     // misses a separator.
 
-                                    // FIXME(xizheyin): This is a hack to avoid adding suggestions for doc comments in item list.
+                                    // This is to avoid adding suggestions twice for doc comments in item list.
                                     let contains_missing_comma_suggestion =
                                         expect_err.suggestions.clone().unwrap_tag().iter().any(
                                             |s| {