Fix(functions4): Update line number in hint

info.toml

@@ -90,7 +90,7 @@ name = "functions4"
 path = "exercises/functions/functions4.rs"
 mode = "compile"
 hint = """
-The error message points to line 12 and says it expects a type after the
+The error message points to line 14 and says it expects a type after the
 `->`. This is where the function's return type should be-- take a look at
 the `is_even` function for an example!"""