Add adw_preferences_group_set_use_markup()
Add adw_preferences_group_set_use_markup(), to be feature complete with libhandy.
Use case:
I just noticed a code in gnome-software saying:
/* AdwPreferencesGroup:use-markup doesn't exist before 1.3.90, configurations
* where GNOME 41 will be used and Libhandy 1.3.90 won't be available are
* unlikely, so let's just ignore the description in such cases. */
#if ADW_CHECK_VERSION(1, 3, 90)
adw_preferences_group_set_description (ADW_PREFERENCES_GROUP (widget), hint);
adw_preferences_group_set_use_markup (ADW_PREFERENCES_GROUP (widget), TRUE);
#endif
which is a leftover from the libhandy usage.