If module name does not specify a file try to load it as a module package instead.

test/language/module/module_package/module.wren

@@ -0,0 +1 @@
+var Index = "index"

test/language/module/package_module.wren

@@ -0,0 +1,3 @@
+import "module_package" for Index
+
+IO.print(Index) // expect: index