Handle item id for heirlooms in the heirloom collection, much like the toy box collection.

GameTooltip.lua

@@ -89,6 +89,14 @@ addon:HookTip("SetGlyphByID", function(self, id)
     addon:AddIDLine(self, "Glyph", id)
 end)
 
+addon:HookTip("SetHeirloomByItemID", function(tip, itemid)
+    -- This won't cause the OnTooltipSetItem to be called, and the tooltip
+    -- won't actually be filled in during the same call either, so we need
+    -- to remember what item it was.
+    tip._alltheid_type = "Item"
+    tip._alltheid_id = itemid
+end) 
+
 addon:HookTip("SetHyperlink", function(self, link)
     local _, _, name, id = strfind(link, "(%w+):(%d+)")
     addon:AddIDLine(self, name:gsub("^%l", string.upper), id)