feat(7z): treat rn command as mode=w

Renaming archive members is a modify operation and can only be done for
formats where writing is supported.

Suggested-by: Ville Skyttä <[email protected]>
Signed-off-by: Kevin Locke <[email protected]>

Author: kevinoid

completions/7z

@@ -11,7 +11,7 @@ _7z()
     fi
 
     local mode
-    [[ ${words[1]} == [adu] ]] && mode=w || mode=r
+    [[ ${words[1]} == @(a|d|rn|u) ]] && mode=w || mode=r
 
     case $cur in
         -ao*)