Update reference TOC

Author: Microsoft Graph DevX Tooling

api-reference/v1.0/toc/security/toc.yml

@@ -186,6 +186,8 @@ items:
       href: ../../api/security-ediscoverycase-post-custodians.md
     - name: List legalHolds
       href: ../../api/security-ediscoverycase-list-legalholds.md
+    - name: Delete legalholds
+      href: ../../api/security-ediscoverycase-delete-legalholds.md
     - name: Create ediscoveryHoldPolicy
       href: ../../api/security-ediscoverycase-post-legalholds.md
     - name: List noncustodialDataSources