Update api style manager docs

src/style_manager/index.js

@@ -9,10 +9,15 @@
  * })
  * ```
  *
- * Once the editor is instantiated you can use its API. Before using these methods you should get the module from the instance
+ * Once the editor is instantiated you can use its API and listen to its events. Before using these methods, you should get the module from the instance.
  *
  * ```js
+ * // Listen to events
+ * editor.on('style:sector:add', (sector) => { ... });
+ *
+ * // Use the API
  * const styleManager = editor.StyleManager;
+ * styleManager.addSector(...);
  * ```
  * ## Available Events
  * * `style:sector:add` - Sector added. The [Sector] is passed as an argument to the callback.