gnu: Use 'gtk-doc/stable' in native-inputs of selected packages.

* gnu/packages/calendar.scm (libical),
gnu/packages/check.scm (umockdev),
gnu/packages/fontutils.scm (libraqm),
gnu/packages/freedesktop.scm (appstream, farstream, libglib-testing)
(udisks, libfprint, libportal),
gnu/packages/geo.scm (memphis, osm-gps-map),
gnu/packages/glib.scm (template-glib),
gnu/packages/gnome.scm (gupnp-igd, libcloudproviders, libgrss, seed)
(gtx, dee, zeitgeist, phodav, gssdp, gupnp, gupnp-dlna, gupnp-av, rygel)
(libnma, gdl, libnotify, vte-ng, dconf, libxklavier, libsoup, colord)
(geoclue, geocode-glib, amtk, grilo, gvfs, gusb, network-manager)
(network-manager-applet, gfbgraph, libunique, cheese, libhandy)
(gnome-latex, libgda),
gnu/packages/gstreamer.scm (orc),
gnu/packages/gtk.scm (at-spi2-core, goocanvas),
gnu/packages/language.scm (nimf),
gnu/packages/networking.scm (libnice),
gnu/packages/video.scm (schroedinger),
gnu/packages/virtualization.scm (libosinfo),
gnu/packages/webkit.scm (wpewebkit, webkitgtk),
gnu/packages/xml.scm (libxmlb)[native-inputs]: Replace 'gtk-doc' with
'gtk-doc/stable'.

gnu/packages/language.scm

@@ -170,7 +170,7 @@
        ("gobject-introspection" ,gobject-introspection)
        ("gtk+-2:bin" ,gtk+-2 "bin")
        ("gtk+:bin" ,gtk+ "bin")
-       ("gtk-doc" ,gtk-doc)
+       ("gtk-doc" ,gtk-doc/stable)
        ("intltool" ,intltool)
        ("libtool" ,libtool)
        ("perl" ,perl)