Update documentation for getElementsAtEventFor Mode (#8803)

The correct properties are `datasetIndex` and `index` without an '_' prefix

diff --git a/docs/developers/api.md b/docs/developers/api.md
index df35ce9af1df260af7119ea2383c0f2c6d570f61..58dad57c66004842efe8ec7f4b235fb038f86209 100644 (file)
--- a/docs/developers/api.md
+++ b/docs/developers/api.md
@@ -107,8 +107,8 @@ function clickHandler(evt) {
 
     if (points.length) {
         const firstPoint = points[0];
-        var label = myChart.data.labels[firstPoint._index];
-        var value = myChart.data.datasets[firstPoint._datasetIndex].data[firstPoint._index];
+        var label = myChart.data.labels[firstPoint.index];
+        var value = myChart.data.datasets[firstPoint.datasetIndex].data[firstPoint.index];
     }
 }
 ```