Docs outdated

https://webtorrent.io/docs seems to be outdated?
[file.getBuffer()](https://webtorrent.io/docs#:~:text=file.getBuffer(function%20callback%20(err%2C%20buffer)%20%7B%7D)) and others don't exist on file. 

https://github.com/webtorrent/webtorrent/blob/master/docs/api.md Reflects the actual api (file.arrayBuffer())
