GtkMenuSectionBox: Add tooltip to iconic buttons
popover: Add show/hide transition
GtkDialog: Connect to activate signals only once

If the widget is an action widget, it's been previously added with
gtk_dialog_add_action_widget, which calls add_response_data on it, which
in turn connects to the clicked/activate signal of that widget, so we
don't need to connect to that signal a second time in
gtk_buildable_custom_finished.
Revert "popover: Add show/hide transition"

This reverts commit 17f48e3a9e3623df2feb76dd209fe80b94b8b5c1.
Revert "GtkMenuSectionBox: Add tooltip to iconic buttons"

This reverts commit 7543e7b279200ed0aad80574c0a3fa2672f297ce.