help-overlay: Improve help overlay

[ghost]

application: Remove excessive show-help-overlay action

We don't need an extra action to show help-overlay. It already managed by GTK. Source: https://docs.gtk.org/gtk4/class.Application.html#automatic-resources

application: Change preferences shortcut

To comply GNOME HIG change preferences shorcut to Ctrl+comma. Source: https://developer.gnome.org/hig/reference/keyboard.html

help-overlay: Use action-name properties

Use action-name properties to avoid repeating shortcut assignments.

[hugolabe]

application: Remove excessive show-help-overlay action

I didn't know it could be done this way. Thank you!

application: Change preferences shortcut

Ok

help-overlay: Use action-name properties

It seems like a good option to me. I think you would also want to change the shortcut for text search Ctrl+F, which also has an action assigned win.search_text

[ghost]

Thanks for reviewing. I fixed the win.search_text action.