still more 'nethack --dumpweights'

After updating the --dumpweights code in hack.c to insert "pair of"
for gloves and boots and "set of" for dragon scales, I've switched
it to use simple_typename() instead.

Turns out that that routine also lacked handling for 'pair|set of'.
And it was generating "coin of gold piece".  Fix those.

Roughly half of the gems are "<gem>" and the others "<gem> stone",
so the --dumpweights output is different by more than just pair/set.

src/hack.c

@@ -4349,25 +4349,15 @@ dump_weights(void)
     for (i = 0; i < ocount; ++i) {
         const char *oc_name = (i == SLIME_MOLD) ? "slime mold"
                               : obj_descr[i].oc_name;
-        int wt = (int) objects[i].oc_weight,
+        int wt = (int) objects[i].oc_weight;
-            ocls = objects[i].oc_class;
 
         if (wt && oc_name) {
             weightlist[cnt].idx = i;
             weightlist[cnt].wt = wt;
             weightlist[cnt].wtyp = 2;
             weightlist[cnt].unique = (objects[i].oc_unique != 0);
-            Snprintf(nmbufbase, sizeof nmbufbase, "%s%s",
+            objects[i].oc_name_known = 1;
-                     (ocls == POTION_CLASS) ? "potion of "
+            Strcpy(nmbufbase, simple_typename(i));
-                     : (ocls == WAND_CLASS) ? "wand of "
-                       : (ocls == SCROLL_CLASS) ? "scroll of "
-                         : (ocls == RING_CLASS) ? "ring of "
-                           : (ocls == SPBOOK_CLASS
-                              && objects[i].oc_name_idx != SPE_BOOK_OF_THE_DEAD
-                              && objects[i].oc_name_idx != SPE_NOVEL)
-                             ? "spellbook of "
-                             : "",
-                     oc_name);
             Snprintf(nmbuf, sizeof nmbuf, "%07u%s", wt,
                      (weightlist[cnt].unique) ? the(nmbufbase)
                                               : an(nmbufbase));

src/objnam.c

@@ -220,8 +220,7 @@ obj_typename(int otyp)
     buf[0] = '\0'; /* redundant */
     switch (ocl->oc_class) {
     case COIN_CLASS:
-        Strcpy(buf, "coin");
+        return strcpy(buf, actualn); /* "gold piece" */
-        break;
     case POTION_CLASS:
         Strcpy(buf, "potion");
         break;
@@ -252,9 +251,17 @@ obj_typename(int otyp)
         if (dn)
             Sprintf(eos(buf), " (%s)", dn);
         return buf;
+    case ARMOR_CLASS:
+        if (objects[otyp].oc_armcat == ARM_GLOVES
+            || objects[otyp].oc_armcat == ARM_BOOTS)
+            Strcpy(buf, "pair of ");
+        else if (otyp >= GRAY_DRAGON_SCALES && otyp <= YELLOW_DRAGON_SCALES)
+            Strcpy(buf, "set of ");
+        FALLTHROUGH;
+        /*FALLTHRU*/
     default:
         if (nn) {
-            Strcpy(buf, actualn);
+            Strcat(buf, actualn);
             if (GemStone(otyp))
                 Strcat(buf, " stone");
             if (un) /* 3: length of " (" + ")" which will enclose 'dn' */
@@ -262,7 +269,7 @@ obj_typename(int otyp)
             if (dn)
                 Sprintf(eos(buf), " (%s)", dn);
         } else {
-            Strcpy(buf, dn ? dn : actualn);
+            Strcat(buf, dn ? dn : actualn);
             if (ocl->oc_class == GEM_CLASS)
                 Strcat(buf,
                        (ocl->oc_material == MINERAL) ? " stone" : " gem");