doc/tutorial: fix errant use of list operators

List operators were removed in 172f006; in 867f71f we introduced
builtins to replace those operators. The tutorial and other guides
should those builtins to demonstrate best practice.

Signed-off-by: Paul Jolly <[email protected]>
Change-Id: Ie595a28ad39e0b13a29355fbbe1ba5a615d18293
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/520994
Unity-Result: CUEcueckoo <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

Author: myitcv

doc/tutorial/basics/2_types/80_lists.txt

@@ -23,7 +23,9 @@ The output contains a valid private IP address (`myIP`)
 and an invalid one (`yourIP`).
 
 -- lists.cue --
-IP: 4 * [ uint8 ]
+import "list"
+
+IP: list.Repeat([ uint8 ], 4)
 
 PrivateIP: IP
 PrivateIP: [10, ...uint8] |