Remove "I AM NOT DONE" and the verify mode and add AppState

exercises/21_macros/macros1.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint macros1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");

exercises/21_macros/macros2.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint macros2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     my_macro!();
 }

exercises/21_macros/macros3.rs

@@ -5,8 +5,6 @@
 // Execute `rustlings hint macros3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 mod macros {
     macro_rules! my_macro {
         () => {

exercises/21_macros/macros4.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint macros4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[rustfmt::skip]
 macro_rules! my_macro {
     () => {