Forward the arguments at the 'delete-surrounding-text' signal
from IBusInputContext to clutter_input_method_delete_surrounding()
so that ibus-typing-booster use the deleting surrounding text function.
Input method engines can delete the output text in applications
with this function.
This change will require a change of mutter of mutter!517
because the first arguemnt of the 'delete-surrounding-text' is INT
to express the offset of the current cursor position but
the first one of clutter_input_method_delete_surrounding() is UINT
since the Wayland spec accepts UINT in delete_surrounding()
mutter will change the type of the first one to INT in
clutter_input_method_delete_surrounding() to work with this change.
https://gitlab.gnome.org/GNOME/mutter/issues/539https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/477
6170bea283