Update TOC.yml

Added Spot Placement Score.

Author: am4234m

articles/virtual-machines/TOC.yml

@@ -1006,6 +1006,8 @@
       href: ./linux/spot-template.md
     - name: Spot Priority Mix
       href: /azure/virtual-machine-scale-sets/spot-priority-mix?toc=/azure/virtual-machines/toc.json
+    - name: Spot Placement Score (Preview)
+      href: /azure/virtual-machines/spot-placement-score.md
     - name: VM size recommendation
       href: /azure/virtual-machine-scale-sets/spot-vm-size-recommendation?toc=/azure/virtual-machines/toc.json
     - name: Error codes