Gtkdoc comments are used, among other things, to generate the various
nm-setting-* manual pages. When a constant is referenced in a gtkdoc
comment (i.e. `%NM_IP_TUNNEL_MODE_IPIP`) it is expanded to show the C name
and the value (i.e. `NM_IP_TUNNEL_MODE_IPIP (1)`). To generate the
nm-setting-* manual pages, we don't use gtkdoc, but we process this data
with the custom script tools/generate-docs-nm-settings-docs-gir.py.
This script was expanding the constants in the same way than gtkdoc.
Showing the constants in that way in nm-setting-* manual pages makes
little sense, because users are not going to use the C identifiers.
Let's show them with a more appropriate format.
Additionally, the different nm-setting-* pages might require different
formats than the other. For example, for nm-setting-nmcli a format like
`"ipip" (1)` is prefered, but for nm-setting-dbus it's better
`1 (ipip)`. Let's generate different nm-settings-docs-gir-*.xml files for
nmcli, dbus, keyfile and ifcfg-rh, using the right format for each one.
f4fbc59a16