Document Alt-Enter for the picker

[bjorn-ove]

I found out about the existence of Alt-Enter when I noticed #7691 being merged. I then tested it in the space-f picker and found it worked there as well. Since this seems to be consistent behavior, I figured it should be documented.

[woojiq]

I wanted to add the docs while working on that PR, but it completely slipped my mind. 👍️
Edit: I think "Open selected without closing picker" would be more informative.

[the-mikedavis]

Suggested change

	| `Alt-Enter` | Open selected in the background |
	| `Alt-Enter` | Open selected without closing the picker |

I agree with woojiq: the "background" part of this might be confusing

[bjorn-ove]

But it doesn't change the current document, it opens hidden, and then you switch to it manually later. Not saying "in the background" is good, but I think "without closing the picker" is more confusing as nothing appears to be happening behind the picker

[bjorn-ove]

I see the point now. It is confusing that the picker doesn't close. But I still think it is also confusing that it doesn't open the focused window, so there is something missing. Perhaps what we would want is Opens selected in the background without closing the picker, however I guess that is too long?

[bjorn-ove]

How about Open in background & keep picker open

[woojiq]

Open selected in the background without closing the picker sounds good. It isn't too long, because if you look at docs you will find even longer description.

[bjorn-ove]

I'm away from my computer until Monday, but will make the change as soon as possible. Feel free to close this PR and make a new one if necessary.

[bjorn-ove]

Updated