mind flayers growing up into master mind flayers, etc.

While one could argue that giant rats aren't just grown up forms of sewer
rats, we already have bat/giant bat in there.

doc/fixes34.1

@@ -200,6 +200,8 @@ prevent "the mimic looks better" on an unrecognized mimic hit with
 	healing spell
 after forcefighting a concealed lurker, the lurker wouldn't fight back
 when polymorphed into a hider, cease hiding during level changes
+let mind flayer grow up into master mind flayer; also giant/sewer rat and
+	cave/large spider
 
 
 Platform- and/or Interface-Specific Fixes