doc: move jdalton to emeritus

In email, John-David Dalton confirmed that it was appropriate to move to
emeritus at this time.

PR-URL: https://github.com/nodejs/node/pull/39380


Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: John-David Dalton <john.david.dalton@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>