feat: update toc

Author: sanposhiho

keps/sig-scheduling/3990-pod-topology-spread-fallback-mode/README.md

@@ -86,12 +86,14 @@ tags, and then generate with `hack/update-toc.sh`.
   - [User Stories (Optional)](#user-stories-optional)
     - [Story 1](#story-1)
     - [Story 2](#story-2)
+    - [Story 3](#story-3)
   - [Notes/Constraints/Caveats (Optional)](#notesconstraintscaveats-optional)
   - [Risks and Mitigations](#risks-and-mitigations)
     - [the fallback could be done when it's actually not needed.](#the-fallback-could-be-done-when-its-actually-not-needed)
 - [Design Details](#design-details)
   - [new API changes](#new-api-changes)
   - [ScaleUpFailed](#scaleupfailed)
+  - [[Beta] <code>scaleupTimeout</code> in the scheduler configuration](#beta-scaleuptimeout-in-the-scheduler-configuration)
     - [How we implement <code>TriggeredScaleUp</code> in the cluster autoscaler](#how-we-implement-triggeredscaleup-in-the-cluster-autoscaler)
   - [PreemptionFalied](#preemptionfalied)
   - [What if are both specified in <code>FallbackCriterion</code>?](#what-if-are-both-specified-in-fallbackcriterion)