For this to work, the default app-id of footclient has been changed
from ‘foot’ to ‘footclient’.
By using distinct StartupWMClasses, the compositor can connect a
running foot/footclient instance to the correct .desktop-file. This
ensures the correct icon is being used in e.g. docks, and that actions
like “open another window” works correctly.
Note that the user can override the app-id, either by setting app-id
in foot.ini, or with the -a,--app-id command line option.
Closes#1355
At least Gnome needs this in order to link running instances of foot
to their corresponding .desktop file, used e.g. when determining which
icon to display for running applications.
Closes#1317