tidbcloud: Update limits (#16271)

tidb-cloud/limitations-and-quotas.md

@@ -15,7 +15,7 @@ TiDB Cloud limits how many of each kind of component you can create in a [TiDB D
 
 | Component | Limit |
 |:-|:-|
-| Number of data replicas | 3 |
+| Number of copies for each [data region](/tidb-cloud/tidb-cloud-glossary.md#region) | 3 |
 | Number of Availability Zones for a cross-zone deployment | 3 |
 
 > **Note:**
@@ -29,3 +29,7 @@ TiDB Cloud limits how many of each kind of component you can create in a [TiDB D
 | Maximum number of total TiDB nodes for all clusters in your organization | 10 |
 | Maximum number of total TiKV nodes for all clusters in your organization | 15 |
 | Maximum number of total TiFlash nodes for all clusters in your organization | 5 |
+
+> **Note:**
+>
+> If any of these limits or quotas present a problem for your organization, please contact [TiDB Cloud Support](/tidb-cloud/tidb-cloud-support.md).