doc: Adding extra doc on atk_remove_[key/global]_event_listener
doc: Adding extra doc on atk_remove_[key/global]_event_listener

Distrotech/atk,Distrotech/atk,Distrotech/atk,GNOME/at-spi2-core,GNOME/at-spi2-core,GNOME/at-spi2-core