[Feature] Have `Alt+F: bindings` on the top right of the screen (when it fits)

[JaredTweed]

I suggested people make edit replace nano as the default, and a complaint I got was that it it was too difficult to figure out how to view the bindings. I think this would solve that.

[lhecker]

I'm hoping to add a command palette in the future which could contain an item to view the bindings, just like what VS Code offers today.