Sure, you can do perldoc Gtk2::TextView, for instance, and get the automatically generated doc for the TextView widget. See Gtk2 TextView doc
What is needed now is an XML guru who will parse the Gtk3 gir file, extract all the elements, and display it in a nice table.
Well, yes, that's fine as a pure reference documentation, however as a tutorial it's somewhat lacking :)
As sparse as the perl Gtk2 docs were, they were better than nothing. I recently tried to do some Perl/Gtk3 scripts, and I literally has to guess at method names. Issues popup without the object heirarchy documentation at your fingertips. I often literally have to guess at the Perl translation of the c libs, and there are numerous overrides which are only talked about on the maillist. You get the idea.