feat: record modules are no longer unimplemented for no fields

refactor: remove some clones and use a ref instead
test: add acceptance test 81

examples/acceptance_tests/081/lib/other.ak

@@ -0,0 +1,4 @@
+pub type Thing {
+  FFF
+  GGG(Int)
+}

examples/acceptance_tests/081/lib/tests.ak

@@ -0,0 +1,15 @@
+use other.{FFF, GGG}
+
+test thing1() {
+  let x =
+    other.FFF
+
+  x == FFF
+}
+
+test thing2() {
+  let x =
+    other.GGG(2)
+
+  x == GGG(2)
+}