[gtkmm-documentation/kjellahl/testci] Add --nonet to xsltproc

[Kjell Ahlstedt <kjellahl src gnome org>]

commit b314a95cb812f5a1924ba326d7305b618ff930e5
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Sun Jan 9 11:27:00 2022 +0100

    Add --nonet to xsltproc

 tools/meson_aux/tutorial-custom-cmd.py | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/tools/meson_aux/tutorial-custom-cmd.py b/tools/meson_aux/tutorial-custom-cmd.py
index 0cc6e73..ae41323 100755
--- a/tools/meson_aux/tutorial-custom-cmd.py
+++ b/tools/meson_aux/tutorial-custom-cmd.py
@@ -68,6 +68,7 @@ def html():
   ] + xslt_params + [
     '-o', output_html_dir + '/',
     '--xinclude',
+    '--nonet',
     xslt_stylesheet,
     input_xml_file,
   ]
@@ -185,6 +186,7 @@ def fop():
   ] + xslt_params + [
     '-o', fo_file,
     '--xinclude',
+    '--nonet',
     xslt_stylesheet,
     input_xml_file,
   ]