Update appmenu layout
Remove separator and change 'About' to 'About Games' to conform with https://gitlab.gnome.org/GNOME/Initiatives/wikis/App-Menu-Retirement
Edited by Alice Mikhaylenko
Remove separator and change 'About' to 'About Games' to conform with https://gitlab.gnome.org/GNOME/Initiatives/wikis/App-Menu-Retirement