Don’t autoplay video on devices with low battery

This is slightly ineffective as the Battery API returns a Promise
_after_ the video has already started auto-playing. But it’s a neat
example for example’s sake.

Author: csswizardry

demo/index.html

@@ -325,6 +325,10 @@ <h2><code>&lt;video&gt;</code> Demo</h2>
           video.preload = 'metadata';
         }
 
+        if (window.obs?.batteryLow === true) {
+          video.autoplay = false;
+        }
+
         videoWrapper.appendChild(video);
 
       }