window-slot: Pass selection by ref
When passing self->pending_selection
by value[1], the actual selection
list is freed by nautilus_view_set_location()
down in [2], thus leaving
a dangling pointer. Pass by reference to avoid that.
[1] https://gitlab.gnome.org/GNOME/nautilus/-/blob/879052b129d922b512faa2c0322b9b66a4d29e08/src/nautilus-window-slot.c?page=2#L1984 [2] https://gitlab.gnome.org/GNOME/nautilus/-/blob/879052b129d922b512faa2c0322b9b66a4d29e08/src/nautilus-window-slot.c?page=3#L2084
Fixes: #3036 (closed)