macros2 solution

exercises/21_macros/macros2.rs

@@ -2,6 +2,7 @@ fn main() {
     my_macro!();
 }
 
+// TODO: Fix the compiler error by moving the whole definition of this macro.
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");

solutions/21_macros/macros2.rs

@@ -1 +1,10 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+// Moved the macro definition to be before its call.
+macro_rules! my_macro {
+    () => {
+        println!("Check out my macro!");
+    };
+}
+
+fn main() {
+    my_macro!();
+}