These actions were not immediately recognizable as icons;
With GMenuModel there's no way to either add tooltips or use
icons _and_ text, so labels-only are the best option
usability-wise.
As per https://gitlab.gnome.org/GNOME/Initiatives/wikis/App-Menu-Retirement,
the new HIG has a few requirements:
* About should be "About <Application Name>"
* Preferences should be in the same section as About and Keyboard Shortcuts
* Shortcuts should be Keyboard Shortcuts
* Quit should be removed, as it's redundant