[gupnp] build: Do not write man page during test

[Jens Georg <jensgeorg src gnome org>]

commit 79a2cb24cd0079e9a025809d11dce13edce68bdd
Author: Jens Georg <mail jensge org>
Date:   Mon Jan 3 18:46:42 2022 +0100

    build: Do not write man page during test
    
    Apparently --noout was the wrong option to not write anything

 doc/meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/doc/meson.build b/doc/meson.build
index 642fc88..c3b8fb3 100644
--- a/doc/meson.build
+++ b/doc/meson.build
@@ -72,6 +72,7 @@ if xsltproc.found()
             xsltproc,
             xlstproc_flags,
             '--noout',
+            '--nowrite',
             stylesheet,
             docbook_man_page
         ]