Instead of "nowhere", say "special" for monsters that do not generate normally.

There have been complaints that "nowhere" is misleading. The generation
property that the bot tells about only concerns the normal monster generation
on the level as you walk around. For example, minotaurs are never randomly
generated but you do see many of them during your run in Gehennom which may
seem "nowhere" seem misplaced.

"special" does not give much information either but it does imply that monsters
may be generated in other ways, thus, being less misleading, I hope.