discovery of enchant weapon scrolls

Eliminate or at least reduce one of the idiosyncratic differences
between enchant weapon and enchant armor:  make reading enchant weapon
discover that scroll if the effect is adequately discernible, instead
of always asking the player to supply a name for it.  If your weapon
is identified and its +/- enchantment value goes up, or you're wielding
a worm tooth and it transforms into a crysknife, you learn the scroll.
However for the negative effect of a cursed one, that's only applicable
when the scroll is already known to be cursed.

doc/fixes34.1

@@ -82,6 +82,7 @@ undo xname FAKE_AMULET_OF_YENDOR AD_DRIN check, the_unique_obj checks this case
 axes should chop trees; picks shouldn't
 chance to aim grappling hook when skilled or better
 level limit of monsters like naga hatchlings should be high enough to grow up
+scroll of enchant weapon will become discovered when read in some cases
 
 
 Platform- and/or Interface-Specific Fixes