doc: Adds rule to xmlformat to help keep spacing right.

The other definitions broke term, cmdsynopsis and arg tags; spaces
inside were removed, making workdsrun-ininstead of keeping them spaced.

Changed files
+4 -3
nixos
+4 -3
nixos/doc/xmlformat.conf
···
entry-break = 0
exit-break = 0
-
-
#term
-
# format inline
+
# This is needed so that the spacing inside those tags is kept.
+
term cmdsynopsis arg
+
normalize yes
+
format block