Improve `prevent-refresh`

[AdamWr]

On this website filmy4wap.co.in there is (I have redacted URL to example.org):

<meta http-equiv="refresh" content="1; URL=https://example.org"/>

and filmy4wap.co.in#%#//scriptlet('prevent-refresh') breaks loading images (not always happen on my end, but if I enable "throttling" in network panel in devtools then it occurs every time).

According to - https://developer.mozilla.org/en-US/docs/Web/HTML/Element/meta#refresh:

The timer starts when the page is completely loaded, which is after the load and pageshow events have both fired.

So maybe we could change it, so window.stop will be called only after load event was fired. Or just add additional option to delay argument, like for example load and window.stop() would be called when load event was fired.