Ignore both unused_element and unused_element_parameter (flutter#152689)

Work towards https://dart-review.googlesource.com/c/sdk/+/378500

Author: srawlins

packages/flutter/lib/src/widgets/widget_inspector.dart

@@ -3455,7 +3455,9 @@ class _Location {
     required this.file,
     required this.line,
     required this.column,
-    // ignore: unused_element
+    // TODO(srawlins): `unused_element_parameter` is being separated from
+    // `unused_element`. Ignore both names until the separation is complete.
+    // ignore: unused_element, unused_element_parameter
     this.name,
   });