Undocumented predicates

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

 has_attribute(Arg1, Arg2)

 has_attribute_value(Arg1, Arg2)

 has_relation(Arg1, Arg2)

 ifmaintainer(Arg1)

 class_of_type(Arg1, Arg2)

 indent(Arg1, Arg2)

 man_classification(Arg1, Arg2)

 man_relation(Arg1)

 class_of(Arg1, Arg2)

 group_objects(Arg1, Arg2)

 super_or_delegate_class(Arg1, Arg2)

 has_relation_value(Arg1, Arg2)

 apropos_class(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6)

 man_attribute(Arg1)