Add a note about a query improvement blocked by upstream

src/Tgstation.Server.Host/Components/Instance.cs

@@ -142,6 +142,8 @@ namespace Tgstation.Server.Host.Components
 			var compileJobsTask = databaseContext.CompileJobs
 				.Where(x => x.Job.Instance.Id == metadata.Id)
 				.OrderByDescending(x => x.Job.StoppedAt)
+				//TODO: Replace with this select when the issues linked in https://github.com/tgstation/tgstation-server/issues/737 are fixed
+				//.Select(x => x.Job.StoppedAt.Value - x.Job.StartedAt.Value)
 				.Select(x => new Job
 				{
 					StoppedAt = x.Job.StoppedAt,