nls: Suppress warnings from po4a Texinfo module.

* po/doc/po4a.cfg (options): Add the "--option no-warn" option to supress the
following warning; "The TexInfo module of po4a is not ready for production
use, and needs a new maintainer.  Please contact the po4a team if you want to
help: send us patches, not bug reports. (use -o no-warn to remove this
message):"

Change-Id: Ic8a2f7d4e54883a05562de72d867d21026f804c6
Signed-off-by: Florian Pelz <pelzflorian@pelzflorian.de>

po/doc/po4a.cfg

@@ -1,5 +1,5 @@
 # GNU Guix --- Functional package management for GNU
-# Copyright © 2024 gemmaro <gemmaro.dev@gmail.com>
+# Copyright © 2024, 2025 gemmaro <gemmaro.dev@gmail.com>
 #
 # This file is part of GNU Guix.
 #
@@ -23,7 +23,8 @@
           --msgid-bugs-address "bug-guix@gnu.org"           \
           --master-charset UTF-8                            \
           --localized-charset UTF-8                         \
-          --keep 0
+          --keep 0                                          \
+          --option no-warn
 
 [po4a_langs] de es fr pt_BR ru zh_CN ko sk sv