Fix return value documentation to use a valid value for 'type'. (#4142) (#4146)

(cherry picked from commit 9322809b3a)

Co-authored-by: Felix Fontein <felix@fontein.de>

plugins/modules/system/xfconf.py

@@ -107,23 +107,26 @@ RETURN = '''
     - The type of the value that was changed (C(none) for C(get) and C(reset)
       state). Either a single string value or a list of strings for array
       types.
+    - This is a string or a list of strings.
     returned: success
-    type: string or list of strings
+    type: any
     sample: '"int" or ["str", "str", "str"]'
   value:
     description:
     - The value of the preference key after executing the module. Either a
       single string value or a list of strings for array types.
+    - This is a string or a list of strings.
     returned: success
-    type: string or list of strings
+    type: any
     sample: '"192" or ["orange", "yellow", "violet"]'
   previous_value:
     description:
     - The value of the preference key before executing the module (C(none) for
       C(get) state). Either a single string value or a list of strings for array
       types.
+    - This is a string or a list of strings.
     returned: success
-    type: string or list of strings
+    type: any
     sample: '"96" or ["red", "blue", "green"]'
 '''