doc improvement for get_colliding_bodies() methods
doc improvement for get_colliding_bodies() methods

(cherry picked from commit 3cd5c86b1a01aeb1f6808175f1914cf39367defe)

pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1