Add a suggestion if macro_rules is misspelled

src/test/ui/parser/misspelled-macro-rules.fixed

@@ -0,0 +1,13 @@
+// Regression test for issue #91227.
+
+// run-rustfix
+
+#![allow(unused_macros)]
+
+macro_rules! thing {
+//~^ ERROR: expected one of
+//~| HELP: perhaps you meant to define a macro
+    () => {}
+}
+
+fn main() {}

src/test/ui/parser/misspelled-macro-rules.rs

@@ -0,0 +1,13 @@
+// Regression test for issue #91227.
+
+// run-rustfix
+
+#![allow(unused_macros)]
+
+marco_rules! thing {
+//~^ ERROR: expected one of
+//~| HELP: perhaps you meant to define a macro
+    () => {}
+}
+
+fn main() {}

src/test/ui/parser/misspelled-macro-rules.stderr

@@ -0,0 +1,10 @@
+error: expected one of `(`, `[`, or `{`, found `thing`
+  --> $DIR/misspelled-macro-rules.rs:7:14
+   |
+LL | marco_rules! thing {
+   | -----------  ^^^^^ expected one of `(`, `[`, or `{`
+   | |
+   | help: perhaps you meant to define a macro: `macro_rules`
+
+error: aborting due to previous error
+