This function modifies the [class@Gtk.TextTag] properties that are related to the
#GtkSourceStyle properties. Other [class@Gtk.TextTag] properties are left untouched.
If @style is non-%NULL, applies @style to @tag.
If @style is %NULL, the related *-set properties of [class@Gtk.TextTag] are set to
%FALSE.
This function modifies the [class@Gtk.TextTag] properties that are related to the #GtkSourceStyle properties. Other [class@Gtk.TextTag] properties are left untouched.
If @style is non-%NULL, applies @style to @tag.
If @style is %NULL, the related *-set properties of [class@Gtk.TextTag] are set to %FALSE.