use actual toplevel answers

src/lib/lists.pl

@@ -131,7 +131,8 @@ member(X, [_|Xs]) :- member(X, Xs).
 %
 % ```
 % ?- select(c, "abcd", X).
-%    X = "abd".
+%    X = "abd"
+% ;  false.
 % ```
 select(X, [X|Xs], Xs).
 select(X, [Y|Xs], [Y|Ys]) :- select(X, Xs, Ys).