fix #H5486 - artifact naming vs illiterate

fix #H5486 - artifact naming vs illiterate

Attempting to name the relevant type of item with an artifact's name
(such as a runesword with "Stormbringer") fails with "your hand
slips" in order to prevent turning the item into an aritfact.  Since
that only happens when the name is valid, it indicates that the hero
is literate so violate illiterate conduct.

(Naming items in general doesn't affect [il]literacy so that player
can assign names to inventory or stash items to maintain notes.)