[PR #10485/15d3ea12 backport][stable-10] remove common return values from docs (#10502)

remove common return values from docs (#10485)

* remove common return values from docs

* pacman: add note about version added of RV

(cherry picked from commit 15d3ea123d)

Co-authored-by: Alexei Znamensky <103110+russoz@users.noreply.github.com>

plugins/modules/xml.py

@@ -340,11 +340,6 @@ actions:
       ],
       "state": "present"
     }
-backup_file:
-  description: The name of the backup file that was created.
-  type: str
-  returned: when O(backup=true)
-  sample: /path/to/file.xml.1942.2017-08-24@14:16:01~
 count:
   description: The count of xpath matches.
   type: int
@@ -354,10 +349,6 @@ matches:
   description: The xpath matches found.
   type: list
   returned: when parameter O(print_match) is set
-msg:
-  description: A message related to the performed action(s).
-  type: str
-  returned: always
 xmlstring:
   description: An XML string of the resulting output.
   type: str