Clarifies behavior

Author: JJ

doc/Type/Nil.pod6

@@ -126,7 +126,7 @@ assigning C<Nil> to a variable which has a default will restore that default.
 
     method append(*@)
 
-Warns the user that they tried to append onto a C<Nil>.
+Warns the user that they tried to append onto a C<Nil> (or derived type object).
 
 =head2 method gist
 
@@ -150,19 +150,19 @@ Returns C<Nil>
 
     method prepend(*@)
 
-Warns the user that they tried to prepend onto a C<Nil>.
+Warns the user that they tried to prepend onto a C<Nil> or derived type object.
 
 =head2 method push
 
     method push(*@)
 
-Warns the user that they tried to push onto a C<Nil>.
+Warns the user that they tried to push onto a C<Nil> or derived type object.
 
 =head2 method unshift
 
     method unshift(*@)
 
-Warns the user that they tried to unshift onto a C<Nil>.
+Warns the user that they tried to unshift onto a C<Nil> or derived type object.
 
 =head2 method ords