we should list () as a way to create List, also show ~~ against ()

Author: gfldex

doc/Type/List.pod6

@@ -64,6 +64,15 @@ Slurpy parameters (C<*@a>) flatten non-itemized sublists:
     say fe(<a b>, <d e>);           # 4
     say fe(<a b>, <d e>.item);      # 3
 
+The emtpy list is created with C<()>. Smartmatching against the empty list will
+check for the absense of elements.
+
+    my @a;
+    for @a, @a.list, @a.Seq -> \listoid {
+        say listoid ~~ ()
+    }
+    # OUTPUT«True␤True␤True␤»
+
 =head1 Methods
 
 =head2 routine elems