feat: move quiz2 to be strings4

info.toml

@@ -167,7 +167,7 @@ For that first compiler error, it's important in Rust that each conditional
 block returns the same type! To get the tests passing, you will need a couple
 conditions checking different input values."""
 
-# TEST 1
+# QUIZ 1
 
 [[exercises]]
 name = "quiz1"
@@ -454,6 +454,12 @@ them!
 For the compose_me method: You can either use the `format!` macro, or convert the string
 slice into an owned string, which you can then freely extend."""
 
+[[exercises]]
+name = "strings4"
+path = "exercises/strings/strings4.rs"
+mode = "compile"
+hint = "No hints this time ;)"
+
 # MODULES
 
 [[exercises]]
@@ -517,8 +523,7 @@ Hint 2: If there is already an entry for a given key, the value returned by `ent
 Learn more at https://doc.rust-lang.org/book/ch08-03-hash-maps.html#updating-a-value-based-on-the-old-value
 """
 
-
-# TEST 2
+# QUIZ 2
 
 [[exercises]]
 name = "quiz2"