customer_portal_guide.md: Update REST API Ref link

Author: adriendupuis

docs/customer_management/customer_portal_guide.md

@@ -118,7 +118,7 @@ Finally, you can customize the registration site itself.
 
 ### REST API
 
-Customer Portal comes with [REST API](https://doc.ibexa.co/en/latest/api/rest_api/rest_api_reference/rest_api_reference.html#corporate-account) for interacting with corporate accounts from the context of the [[= product_name_connect =]] app.
+Customer Portal comes with [REST API](/api/rest_api/rest_api_reference/rest_api_reference.html#tag/Corporate-Account) for interacting with corporate accounts from the context of the [[= product_name_connect =]] app.
 
 ## Capabilities
 
@@ -181,4 +181,4 @@ Thus, reducing the need to allocate resources to extend working hours or hire mo
 
 ### Localization and personalization
 
-The use of Page Builder in the Customer Portal creation process enables you to create unique experiences for each business customer based on their location, business type, company, or market they operate on.
+The use of Page Builder in the Customer Portal creation process enables you to create unique experiences for each business customer based on their location, business type, company, or market they operate on.