gioenums: Add deprecation for FLAGS_NONE
g-ir won't pick it if it is not in its own doc block.
Requires gobject-introspection!512 (merged), otherwise the deprecated tag won't be set in the introspection data.
g-ir won't pick it if it is not in its own doc block.
Requires gobject-introspection!512 (merged), otherwise the deprecated tag won't be set in the introspection data.