Store deprecation information for types in the gir
If I add Deprecated: 3.10: FOO
to a type description it correctly strips it away for the doc field in the gir but there is no deprecation information in the gir.
Use case: I want display if a type is deprecated in the Python docs. Currently for things like https://lazka.github.io/pgi-docs/#Gtk-3.0/classes/ImageMenuItem.html#Gtk.ImageMenuItem only all methods/properties are deprecated but not the type itself.