Update sql-server-failover-cluster-installation.md (#27416)

Update in relation to CSS case number 2304040050000494, where installation is failing due to the requirement of a RWDC.

Co-authored-by: Stewart Hands <86346990+StewartHandsMSFT@users.noreply.github.com>
Co-authored-by: Shannon Leavitt <47186198+ShannonLeavitt@users.noreply.github.com>

Author: 3 people

docs/sql-server/failover-clusters/install/sql-server-failover-cluster-installation.md

@@ -37,7 +37,8 @@ ms.custom: intro-installation
 4.  SQL Server failover cluster instance (FCI) requires the cluster nodes to be domain joined. The following configurations are **not supported**:
     - SQL FCI on workgroup clusters. 
     - SQL FCI on Multi-Domain cluster.   
-    - SQL FCI on Domain + Workgroup Clusters. 
+    - SQL FCI on Domain + Workgroup Clusters.
+    - SQL FCI when Read Only Domain Controllers (RODC) are available.
 
 ## [!INCLUDE[ssNoVersion](../../../includes/ssnoversion-md.md)] Failover Cluster Installation options