Add `buffer_editor` example using arguments to `sample_config.nu`

Reminder (really a note-to-self) to update `doc_config.nu` based on [this comment](https://github.com/nushell/nushell.github.io/pull/1656#discussion_r1867975400).  It's a main repo change, but tracking it here since it is really "doc".

Also, based on https://github.com/nushell/nushell/issues/14893 - We should add this to the QuickStart Config section.