Update support.md

Added a note:

Customers can only log Severity 3 tickets for single replica services across tiers. The exception is for a service leveraging the compute-compute separation feature, where the parent service is running 3+ replicas.

Author: krithika-ch

docs/en/about-us/support.md

@@ -7,7 +7,7 @@ sidebar_position: 30
 
 ClickHouse provides Support Services for our ClickHouse Cloud users and customers. Our objective is a Support Services team that represents the ClickHouse product – unparalleled performance, ease of use, and exceptionally fast, high-quality results. For details, [visit our Support Services](https://clickhouse.com/support/program/) page.
 
-[Login to the Cloud console](https://clickhouse.cloud/support) and select **Help -> Support** from the menu options to open a new support case and view the status of your submitted cases.
+[Login to the Cloud console](https://clickhouse.cloud/support) and select **Help -> Support** from the menu options to open a new support case and view the status of your submitted cases. Customers can only log Severity 3 tickets for single replica services across tiers. The exception is for a service leveraging the compute-compute separation feature, where the parent service is running 3+ replicas.
 
 You can also subscribe to our [status page](https://status.clickhouse.com) to get notified quickly about any incidents affecting our platform.