Update line-split docs to make end result more clear

Author: luc-tielen

packages/turf-line-split/README.md

@@ -20,7 +20,10 @@ var splitter = turf.lineString([[130, -15], [130, -35]]);
 var split = turf.lineSplit(line, splitter);
 
 //addToMap
-var addToMap = [line, splitter]
+var addToMap = [line, splitter, split]
+
+split.features[0].properties.stroke = "red";
+split.features[1].properties.stroke = "blue";
 ```
 
 Returns **[FeatureCollection][3]<[LineString][2]>** Split LineStrings

packages/turf-line-split/index.js

@@ -24,6 +24,9 @@ import { lineString, featureCollection } from "@turf/helpers";
  *
  * //addToMap
  * var addToMap = [line, splitter, split]
+ *
+ * split.features[0].properties.stroke = "red";
+ * split.features[1].properties.stroke = "blue";
  */
 function lineSplit(line, splitter) {
   if (!line) throw new Error("line is required");