Restore a one-line example.

Not everybody agreed this example was redundant.

Author: dumarchie

doc/Type/independent-routines.pod6

@@ -1224,6 +1224,8 @@ container is empty.
 
 Example:
 
+    say shift [1,2]; # OUTPUT: «1␤»
+
 =for code
 my @a of Int = [1];
 say shift @a; # OUTPUT: «1␤»