Remove tension option backwards compatibility (#6692)

docs/getting-started/v3-migration.md

@@ -29,6 +29,7 @@ Chart.js is no longer providing the `Chart.bundle.js` and `Chart.bundle.min.js`.
 
 ### Options
 
+* The dataset option `tension` was renamed to `lineTension`
 * `scales.[x/y]Axes.barPercentage` was moved to dataset option `barPercentage`
 * `scales.[x/y]Axes.barThickness` was moved to dataset option `barThickness`
 * `scales.[x/y]Axes.categoryPercentage` was moved to dataset option `categoryPercentage`

src/controllers/controller.line.js

@@ -82,11 +82,6 @@ module.exports = DatasetController.extend({
 
 		// Update Line
 		if (showLine) {
-			// Compatibility: If the properties are defined with only the old name, use those values
-			if (config.tension !== undefined && config.lineTension === undefined) {
-				config.lineTension = config.tension;
-			}
-
 			// Utility
 			line._datasetIndex = me.index;
 			// Data