Remove references to application menu for 3.32
If the app menu goes away in 3.32 then the files
- https://gitlab.gnome.org/GNOME/gnome-user-docs/blob/master/gnome-help/C/figures/shell-appmenu-shell.png
- https://gitlab.gnome.org/GNOME/gnome-user-docs/blob/master/gnome-help/C/figures/shell-appmenu-classic.png should go and the text wherever they are used needs to get updated.
Regarding text, https://wiki.gnome.org/DocumentationProject/Guide/LanguageStyle says instructions are to be replaced by Press the menu button in the top-right corner of the window and select <gui style="menuitem">Blah</gui>.
$:acko\> grep -r "pplication menu" .
./shell-introduction.page: <title>Application menu</title>
./shell-introduction.page: <p>Application menu, located beside the <gui>Activities</gui> button,
./shell-introduction.page: are available in the application menu vary depending on the application.
./shell-introduction.page: <p>Application menu, located next to the <gui>Applications</gui> and
./shell-introduction.page: preferences or help. The items that are available in the application menu
./keyboard-shortcuts-set.page: <td><p>Open the application menu</p></td>
./keyboard-nav.page: <td><p>Open the application menu on the top bar.</p></td>