database: support negative levels in quest links

This allows for a negative value in the quest link for some quests in wotlk.
Example: https://www.wowhead.com/wotlk/quest=1528/call-of-water

database.lua

@@ -1453,7 +1453,7 @@ function pfDatabase:GetQuestIDs(qid)
   if GetQuestLink then
     local questLink = GetQuestLink(qid)
       if questLink then
-      local _, _, id = strfind(questLink, "|c.*|Hquest:([%d]+):([%d]+)|h%[(.*)%]|h|r")
+      local _, _, id = strfind(questLink, "|c.*|Hquest:([%d]+):([-]?[%d]+)|h%[(.*)%]|h|r")
       if id then return { [1] = tonumber(id) } end
     end
   end