Make a video / screenshots demo of some features

[WofWca]

There are some cool "lifehacks" that are not always immediately obvious to users. Like

• The fact that there are hotkeys. You have to go to the options page to figure that out. Maybe need a screenshot, like here https://github.com/igrigorik/videospeed#faster-html5-video.
• The fact that you can use hotkeys (like pause/unpause, seeking) in the popup, so you don't have to close it every time.
• The fact that you can open the popup with a hotkey as well.
• Pausing the video by clicking on the chart.
• Chromium's website whitelist function (see #26)
• https://github.com/WofWca/jumpcutter/issues/27#issuecomment-927101178

I might have missed something, would love to hear some more from you all.

Maybe need to show all of it off on the demonstration video, the current one is a little grotesque, or just screenshots (although there can't be too many of them).