Remove all the old 2.x and 3.x version annotations.
GTK+ 4 is a new start, and from the perspective of a
GTK+ 4 developer all these APIs have been around since
the beginning.
The inspector may hold on to render nodes and textures
beyond the lifetime of the widget (and thus the GL
resources). To handle this situation, allow the widget
to explicitly release the GL resources, and make
the texture available on the clent-side as a cairo
surface. This lets the recorder still show the content
after the widget is gone.
and gdk_texture_new_from_resource().
While doing set, turn all GDK_AVAILABLE_IN_3_90 into
GDK_AVAILABLE_IN_3_94 because that's now true after the renaming.
