Update index.d.ts

Add style api

types/datatables.net-select/index.d.ts

@@ -46,4 +46,17 @@ declare namespace DataTables {
          */
         style?: string;
     }
+    
+    interface Api {
+        select: {
+          /*
+          * Get the current selection style applied to the table
+          */
+          style(): string;
+          /*
+          * Set the table's selection style
+          */
+          style(s: "api" | "single" | "multi" | "os"): Api;
+        }
+    }
 }