add tidy warning for "tidy-ignore"

Fixes #130984.
Tidy now warns on seeing the typo "tidy-ignore-{CHECK}" (it's actually "ignore-tidy").

src/tools/tidy/src/style.rs

@@ -474,6 +474,9 @@ pub fn check(path: &Path, bad: &mut bool) {
                 suppressible_tidy_err!(err, skip_cr, "CR character");
             }
             if !is_this_file {
+                if line.contains("tidy-ignore") {
+                    err("use ignore-tidy-[check], not tidy-ignore-[check]");
+                }
                 // Allow using TODO in diagnostic suggestions by marking the
                 // relevant line with `// ignore-tidy-todo`.
                 if trimmed.contains("TODO") && !trimmed.contains("ignore-tidy-todo") {