Undocumented predicates

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

 context_name(Arg1, Arg2)

 with_value(Arg1, Arg2, Arg3)

 with_value(Arg1, Arg2, Arg3, Arg4)

 get_context_value(Arg1, Arg2)

 set_context_value(Arg1, Arg2)

 nb_set_context_value(Arg1, Arg2)

 current_context_value(Arg1, Arg2)

 with_context_values(Arg1, Arg2, Arg3)

 with_context_values(Arg1, Arg2, Arg3, Arg4)

 with_context_value(Arg1, Arg2, Arg3)

 with_context_value(Arg1, Arg2, Arg3, Arg4)

 without_context_value(Arg1, Arg2)

 without_context_value(Arg1, Arg2, Arg3)