Undocumented predicates

The following predicates are exported, but not or incorrectly documented.

 new_vector(Arg1)

 new_vector(Arg1, Arg2)

 v_ref(Arg1, Arg2, Arg3)

 v_size(Arg1, Arg2)

 v_max(Arg1, Arg2)

 v_member(Arg1, Arg2)

 new_index(Arg1, Arg2, Arg3)

 new_index(Arg1, Arg2, Arg3, Arg4)