Per-Rarity Quest Completion Placeholders

Building on the PlaceholderAPI integration from v1.1.6, you can now track how many quests each player has completed at every rarity tier, perfect for tiered leaderboards, role rewards, and player stat displays.

• 5 new placeholders for per-rarity completion counts:
• %scrollquest_completed_common% - Total Common quests completed
• %scrollquest_completed_uncommon% - Total Uncommon quests completed
• %scrollquest_completed_rare% - Total Rare quests completed
• %scrollquest_completed_epic% - Total Epic quests completed
• %scrollquest_completed_legendary% - Total Legendary quests completed
• Case-insensitive - works with any capitalization
• Fully backward compatible - existing %scrollquest_completed% total still works, no config changes needed
• No data loss - existing player-stats.yml files load fine, new completions start tracking per-rarity from this update onward