auto-reload option

[1925381584]

hi, I think the option of auto-reload to let the buffer auto revert is useful.
when it open, the buffer changed outside will be sync into inside auto, if the buffer changed inside also, Give a hint whether to force an override. does it has exist?

[the-mikedavis]

See #1125, we need a file system monitor (which @pascalkuthe is working on as time allows) to be able to pick up on external changes