Undocumented predicates

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

 declaration(Arg1)

 declaration(Arg1, Arg2)

 global(Arg1)

 global(Arg1, Arg2)

 type(Arg1)

 type(Arg1, Arg2)

 checkprop_goal(Arg1)

 compat(Arg1)

 compat(Arg1, Arg2)

 with_cv_module(Arg1, Arg2)

 cv_module(Arg1)

 instan(Arg1)

 instan(Arg1, Arg2)

 last_prop_failure(Arg1)