wmmenugen: Use 'Other' instead of 'Applications' for unknown categories.
From https://standards.freedesktop.org/menu-spec/latest/apa.html:
Category-based menus based on the Main Categories listed in this
specification do not provide a complete ontology for all available
applications. Category-based menu implementations SHOULD therefore provide
a "catch-all" submenu for applications that cannot be appropriately placed
elsewhere.
Emphasis on *submenu*. By using 'Applications', these menu entries were
sorted into the top level.