docs: automatically set dns service address

Signed-off-by: Dario Tranchitella <dario@tranchitella.eu>

docs/content/reference/api.md

@@ -13937,9 +13937,9 @@ Use this field to add additional hostnames when exposing the Tenant Control Plan
         <td><b>dnsServiceIPs</b></td>
         <td>[]string</td>
         <td>
-          <br/>
-          <br/>
-            <i>Default</i>: [10.96.0.10]<br/>
+          The DNS Service for internal resolution, it must match the Service CIDR.
+In case of empty value, the value is automatically computed according to the Service CIDR + 10 bits, e.g.:
+Service CIDR 10.96.0.0/16, the resulting DNS Service IP will be 10.96.0.10<br/>
         </td>
         <td>false</td>
       </tr><tr>
@@ -13959,7 +13959,7 @@ Example: {"192.168.1.0/24", "10.0.0.0/8"}<br/>
         <td><b>podCidr</b></td>
         <td>string</td>
         <td>
-          CIDR for Kubernetes Pods<br/>
+          CIDR for Kubernetes Pods: if empty, defaulted to 10.244.0.0/16.<br/>
           <br/>
             <i>Default</i>: 10.244.0.0/16<br/>
         </td>
@@ -13978,7 +13978,7 @@ Example: {"192.168.1.0/24", "10.0.0.0/8"}<br/>
         <td><b>serviceCidr</b></td>
         <td>string</td>
         <td>
-          Kubernetes Service<br/>
+          CIDR for Kubernetes Services: if empty, defaulted to 10.96.0.0/16.<br/>
           <br/>
             <i>Default</i>: 10.96.0.0/16<br/>
         </td>