Add macros solutions

exercises/macros/macros1.rs

@@ -1,8 +1,6 @@
 // macros1.rs
 // Make me compile! Execute `rustlings hint macros1` for hints :)
 
-// I AM NOT DONE
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
@@ -10,5 +8,5 @@ macro_rules! my_macro {
 }
 
 fn main() {
-    my_macro();
+    my_macro!();
 }

exercises/macros/macros2.rs

@@ -1,14 +1,12 @@
 // macros2.rs
 // Make me compile! Execute `rustlings hint macros2` for hints :)
 
-// I AM NOT DONE
-
-fn main() {
-    my_macro!();
-}
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
     };
 }
+
+fn main() {
+    my_macro!();
+}

exercises/macros/macros3.rs

@@ -2,8 +2,7 @@
 // Make me compile, without taking the macro out of the module!
 // Execute `rustlings hint macros3` for hints :)
 
-// I AM NOT DONE
-
+#[macro_use]
 mod macros {
     macro_rules! my_macro {
         () => {

exercises/macros/macros4.rs

@@ -1,15 +1,13 @@
 // macros4.rs
 // Make me compile! Execute `rustlings hint macros4` for hints :)
 
-// I AM NOT DONE
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
-    }
+    };
     ($val:expr) => {
         println!("Look at this other macro: {}", $val);
-    }
+    };
 }
 
 fn main() {