Undocumented predicates

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

 solve_=(Arg1, Arg2)

 solve_=\=(Arg1, Arg2)

 backsubst(Arg1, Arg2, Arg3, Arg4)

 backsubst_delta(Arg1, Arg2, Arg3, Arg4, Arg5)

 basis_add(Arg1, Arg2)

 bs(Arg1, Arg2, Arg3, Arg4)

 dec_step(Arg1, Arg2, Arg3)

 deref(Arg1, Arg2, Arg3)

 deref_var(Arg1, Arg2, Arg3)

 export_binding(Arg1)

 inc_step(Arg1, Arg2, Arg3)

 intro_at(Arg1, Arg2, Arg3, Arg4)

 lb(Arg1, Arg2, Arg3, Arg4)

 lb(Arg1, Arg2, Arg3, Arg4, Arg5)

 log_deref(Arg1, Arg2, Arg3, Arg4, Arg5)

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

 pivot_a(Arg1, Arg2, Arg3, Arg4, Arg5)

 pivot_b(Arg1, Arg2, Arg3, Arg4, Arg5)

 rcbl(Arg1, Arg2, Arg3, Arg4)

 rcbl_status(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7)

 reconsider(Arg1, Arg2)

 same_class(Arg1, Arg2)

 select_active_bound(Arg1, Arg2)

 solve(Arg1, Arg2)

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

 solve_ord_x(Arg1, Arg2, Arg3, Arg4)

 ub(Arg1, Arg2, Arg3, Arg4)

 ub(Arg1, Arg2, Arg3, Arg4, Arg5)

 unconstrained(Arg1, Arg2, Arg3, Arg4, Arg5)

 var_with_def_intern(Arg1, Arg2, Arg3, Arg4, Arg5)