sample-code: Add example "module-hell.cl" demonstrating inter-module imports and path resolution

sample-code/module_hell.cl

@@ -0,0 +1,17 @@
+//! Demonstrates modules
+
+fn main() {
+    use foo::bar::baz; // -> use super::baz::qux as baz: 10 -> fn baz::qux: 12
+    baz()
+}
+
+mod foo {
+    mod bar {
+        use super::baz::qux as baz; // -> fn qux: 14
+    }
+    mod baz {
+        fn qux() {
+            print("foo, bar, baz, qux")
+        }
+    }
+}