fix: pass correct this object to WebSocket close handler.

As Firefox calls onclose when navigating away this led to the setTimeout running instantly because of a timeout of `undefined` which then led to a reload of the page which breaks navigating away.

src/autoreload.js

@@ -90,7 +90,7 @@
                         break;
                 }
             };
-            ws.onclose = this.onclose;
+            ws.onclose = () => this.onclose();
         }
 
         onclose() {