Change lint_dropping_copy_types to use UseLetUnderscoreIgnoreSuggestion as suggestion.

compiler/rustc_lint/src/lints.rs

@@ -691,20 +691,7 @@ pub struct DropCopyDiag<'a> {
     #[label]
     pub label: Span,
     #[subdiagnostic]
-    pub sugg: DropCopySuggestion,
-}
-
-#[derive(Subdiagnostic)]
-pub enum DropCopySuggestion {
-    #[note(lint_note)]
-    Note,
-    #[multipart_suggestion(lint_suggestion, style = "verbose", applicability = "maybe-incorrect")]
-    Suggestion {
-        #[suggestion_part(code = "let _ = ")]
-        start_span: Span,
-        #[suggestion_part(code = "")]
-        end_span: Span,
-    },
+    pub sugg: UseLetUnderscoreIgnoreSuggestion,
 }
 
 #[derive(LintDiagnostic)]