adding typing for tooltip order (#22997)

types/c3/c3-tests.ts

@@ -1847,6 +1847,20 @@ function tooltip_format() {
     });
 }
 
+function tooltip_order() {
+    const chart = c3.generate({
+        data: {
+            columns: [
+                ["data1", 30, 200, 100, 400, 150, 250],
+                ["data2", 50, 20, 10, 40, 15, 25]
+            ]
+        },
+        tooltip: {
+            order: 'asc'
+        }
+    });
+}
+
 ////////////////////////
 // Chart options Tests
 ////////////////////////

types/c3/index.d.ts

@@ -737,6 +737,10 @@ export interface TooltipOptions {
      * Specified function receives data, defaultTitleFormat, defaultValueFormat and color of the data point to show. If tooltip.grouped is true, data includes multiple data points.
      */
     contents?(data: any, defaultTitleFormat: string, defaultValueFormat: string, color: any): string;
+    /**
+     * Set tooltip values order
+     */
+    order?: string | any[] | ((data: Data) => boolean);
 }
 
 export interface SubchartOptions {