fix: Call zoomChanged event after updating the zoom

The zoomChange method was not being called on the extensions, and this
commit fixes this by calling the runExtensions method after updating the
zoom.
This commit addresses issue #896

src/editor/Editor.js

@@ -824,6 +824,7 @@ class Editor extends EditorStartup {
    * @param {module:svgcanvas.SvgCanvas#event:zoomed} bbox
    * @param {boolean} autoCenter
    * @listens module:svgcanvas.SvgCanvas#event:zoomed
+   * @fires module:svgcanvas.SvgCanvas#event:ext_zoomChanged
    * @returns {void}
    */
   zoomChanged (win, bbox, autoCenter) {
@@ -865,6 +866,11 @@ class Editor extends EditorStartup {
     }
 
     this.zoomDone()
+
+    this.svgCanvas.runExtensions(
+      'zoomChanged',
+      /** @type {module:svgcanvas.SvgCanvas#event:ext_zoomChanged} */ this.svgCanvas.getZoom()
+    )
   }
 
   /**