The type of the variable window is GtkWidget. Rename the variable
from window to widget, because windows and widgets are different
things.

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Message-Id: <20201213165724.13418-2-vr_qemu@t-online.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>