feat!: drop modules, general refactor and cleanup

runtime/queries/rust/folds.scm

@@ -0,0 +1,25 @@
+[(mod_item)
+ (function_item)
+ (struct_item)
+ (trait_item)
+ (enum_item)
+ (impl_item)
+ (type_item)
+ (union_item)
+
+ (use_declaration)
+ (let_declaration)
+
+ (loop_expression)
+ (for_expression)
+ (while_expression)
+ (if_expression)
+ (match_expression)
+ (call_expression)
+ (array_expression)
+
+ (macro_definition)
+ (macro_invocation)
+
+ (attribute_item)
+] @fold