Update Exercises Directory Names to Reflect Order

exercises/17_tests/tests2.rs

@@ -0,0 +1,17 @@
+// tests2.rs
+//
+// This test has a problem with it -- make the test compile! Make the test pass!
+// Make the test fail!
+//
+// Execute `rustlings hint tests2` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn you_can_assert_eq() {
+        assert_eq!();
+    }
+}