Fix error parameter annotations
Review Request #2019 — Created Nov. 4, 2022 and submitted
(optional)annotation causes a warning because the parameter is not marked as
(out). Additionally, the annotations have no effect on the generated documentation.
When a function takes
GError **error, then the GObject introspection data includes
When gi-docgen sees that annotation, it inserts a standard text about it, so what we write there doesn't matter too much. It will only be seen by people reading the header file directly, so I have inserted a consistent text in those places.
Compiled and saw fewer warnings from gobject-introspection.