Add OCaml folds

queries/ocaml/folds.scm

@@ -0,0 +1,30 @@
+[
+  (let_binding)
+  (external)
+  (type_binding)
+  (exception_definition)
+  (module_binding)
+  (module_type_definition)
+  (open_module)
+  (include_module)
+  (include_module_type)
+  (class_binding)
+  (class_type_binding)
+  (value_specification)
+  (inheritance_specification)
+  (instance_variable_specification)
+  (method_specification)
+  (inheritance_definition)
+  (instance_variable_definition)
+  (method_definition)
+  (class_initializer)
+  (match_case)
+  (attribute)
+  (item_attribute)
+  (floating_attribute)
+  (extension)
+  (item_extension)
+  (quoted_extension)
+  (quoted_item_extension)
+  (comment)
+] @fold