Variable expansion breaks on empty `$someone` + `$heshe`/`$himher`

[dgw]

Quick example from a silly game my users added years ago:

<~dgw> !mylife
<&Kaede> dgw will grow to be very subterranian. $Heshe will $verb $adverb, and often. $Heshe will develop an unhealthy obsession for $nouns, even reaching the point of attempting to marry one. However, their childhood friend someone will intervene, returning them to sanity just in time, and $heshe will instead marry the one who saved $himher.

Emphasis added to show what seems to be the cause: $someone resolving to a literal "someone", i.e. no one else has spoken recently so there is no nick for which to fetch gender info if $heshe, $himher, etc. get used.

Fix is probably "as simple as" automatically returning the "they/them" pronoun set in this case.