fix wrong help message for taint

pkg/kubectl/cmd/taint.go

@@ -59,7 +59,7 @@ var (
 
 		* A taint consists of a key, value, and effect. As an argument here, it is expressed as key=value:effect.
 		* The key must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to %[1]d characters.
-		* The value must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to %[1]d characters.
+		* The value must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to %[2]d characters.
 		* The effect must be NoSchedule or PreferNoSchedule.
 		* Currently taint can only apply to node.`)