Order hint completion alerts chronologically

Instead of sorting hint completion alerts alphabetically
just so they'll be stable, sort them by order of actual
completion, so most recently completed hints are at
the bottom of the list, instead of inserted at randomish
places in the list.

mods/nc_api_hints/alerts.lua

@@ -43,14 +43,18 @@ nodecore.register_playerstep({
 
 			local mc = msgcache[data.pname] or {}
 			local t = {}
+			local o = {}
 			for k, v in pairs(mc) do
 				if v < nodecore.gametime then
 					mc[k] = nil
 				else
 					t[#t + 1] = nodecore.translate(msg, k)
+					o[t[#t]] = v
 				end
 			end
-			table_sort(t)
+			table_sort(t, function(a, b)
+					return o[a] < o[b] or o[a] == o[b] and a < b
+				end)
 			nodecore.hud_set_multiline(player, {
 					label = "hintcomplete",
 					hud_elem_type = "text",