Merge branch 'master' into refactor-hints

exercises/strings/strings1.rs

@@ -2,6 +2,8 @@
 // Make me compile without changing the function signature!
 // Execute `rustlings hint strings1` for hints ;)
 
+// I AM NOT DONE
+
 fn main() {
     let answer = current_favorite_color();
     println!("My current favorite color is {}", answer);

exercises/strings/strings2.rs

@@ -2,6 +2,8 @@
 // Make me compile without changing the function signature!
 // Execute `rustlings hint strings2` for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
     if is_a_color_word(word) {