fix issue #326 - can't wish for were-foo corpse

"were{rat,jackal,wolf}" each occur twice in mons[], once for the
beast form and second time among '@' for the human form.  Wishing
for werecreature corpse or tin always matches the first entry so
yields the beast form, but all their beast forms are flagged as
no-corpse so the wish would fallback to a corpse with random monster
type.  Wishing for werecreature figurine worked but always produced
one that created its beast form if/when activated.

This fix allows specifying "human werecreature" to match the second
entry.  It's optional for corpse and tin; the wish code will now
switch to that implicitly if it gets a no-corpse were-form for
those.  It has to be specified explicitly to get a figurine that
will activate as the human form.  It works for ^G too.

Fixes #326

src/mondata.c

@@ -770,6 +770,15 @@ const char **remainder_p;
             { "woodland nymph", PM_WOOD_NYMPH },
             { "halfling", PM_HOBBIT },    /* potential guess for polyself */
             { "genie", PM_DJINNI }, /* potential guess for ^G/#wizgenesis */
+            /* prefix used to workaround duplicate monster names for
+               monsters with alternate forms */
+            { "human wererat", PM_HUMAN_WERERAT },
+            { "human werejackal", PM_HUMAN_WEREJACKAL },
+            { "human werewolf", PM_HUMAN_WEREWOLF },
+            /* for completeness */
+            { "rat wererat", PM_WERERAT },
+            { "jackal werejackal", PM_WEREJACKAL },
+            { "wolf werewolf", PM_WEREWOLF },
             /* Hyphenated names -- it would be nice to handle these via
                fuzzymatch() but it isn't able to ignore trailing stuff */
             { "ki rin", PM_KI_RIN },