Lowercase 'of' in custom potion names to match vanilla
Vanilla potions display as 'Potion of X' but every custom potion in potions.yml says 'Potion Of X'. All 90 names now match the vanilla capitalization. Purely cosmetic: recipe matching compares effects, base type and lore, never display names, so existing brewed potions still match. (commit: ea678b7)
