Documents list → on the list side, closes #1245

Author: JJ

doc/Type/List.pod6

@@ -1270,6 +1270,23 @@ It does nothing, and returns C<Nil>, as the definition clearly shows.
 
     sink [1,2,Failure.new("boo!"),"still here"]; # OUTPUT: «»
 
+=head2 method Set
+
+In general, creates a set which has as members elements of the list.
+
+    say <æ ß þ €>.Set ;# OUTPUT: «set(ß æ þ €)␤»
+
+However, there might be some unexpected changes in case the list includes
+non-scalar data structures. For instance, with L<Pair>s:
+
+    my @ary = (:42a, :33b);
+    say @ary.Set;# OUTPUT: «set(a b)␤»
+
+The set will be composed of the C<key>s of the Pair whose corresponding value
+is not 0, eliminating all the values. Please check the
+L<C<Set> documentation|/type/Set#Creating_Set_objects> for more examples and a
+more thorough explanation.
+
 =head1 Operators
 
 =head2 infix C«cmp»