Fix bonuses for enchanted, unidentified rings

[flend]

Fixes issue #602.

• Unidentified rings can no longer have higher bonuses than they will have once identified
• Unidentified positive rings give 1 + timesEnchanted prior to identification, not 1 + timesEnchanted - 1

Test evidence:

Unidentified +1 ring of regen, 2 enchants

1774        if (theItem->category != RING) {
(gdb) n
1777        if (!(theItem->flags & ITEM_IDENTIFIED)
(gdb)
1782            return min(theItem->enchant1, theItem->timesEnchanted + 1);
(gdb) print theItem->enchant1
$1 = 3
(gdb) print theItem->timesEnchanted
$2 = 2
(gdb) n
updateRingBonuses () at src/brogue/Items.c:7776
7776                        break;
(gdb) print rogue.regenerationBonus
$3 = 3

Unidentified +3 ring of regen, 3 enchants

1774        if (theItem->category != RING) {
(gdb) n
1777        if (!(theItem->flags & ITEM_IDENTIFIED)
(gdb)
1782            return min(theItem->enchant1, theItem->timesEnchanted + 1);
(gdb) print theItem->enchant1
$4 = 6
(gdb) print theItem->timesEnchanted
$5 = 3
(gdb) n
updateRingBonuses () at src/brogue/Items.c:7776
7776                        break;
(gdb) print rogue.regenerationBonus
$6 = 4

Unidentified -3 ring of regen, 4 enchants

1774        if (theItem->category != RING) {
(gdb) n
1777        if (!(theItem->flags & ITEM_IDENTIFIED)
(gdb)
1782            return min(theItem->enchant1, theItem->timesEnchanted + 1);
(gdb) print theItem->enchant1
$1 = 1
(gdb) print theItem->timesEnchanted
$2 = 4
(gdb) n
updateRingBonuses () at src/brogue/Items.c:7776
7776                        break;
(gdb) print rogue.regenerationBonus
$3 = 1
(gdb) c
Continuing.

Identifying ring

Thread 1 "brogue" hit Breakpoint 1, effectiveRingEnchant (theItem=0x555556e51770) at src/brogue/Items.c:1774
1774        if (theItem->category != RING) {
(gdb) n
1777        if (!(theItem->flags & ITEM_IDENTIFIED)
(gdb) n
1784        return theItem->enchant1;
(gdb) print theItem->enchant1
$4 = 1
(gdb) n
updateRingBonuses () at src/brogue/Items.c:7776
7776                        break;
(gdb) print rogue.regenerationBonus
$5 = 1
(gdb)

[tmewett]

LGTM, good catch