docs: add contentSourcePath to DeliveryConfig schema (#2154)

JIRA: https://jira.corp.adobe.com/browse/SITES-41284

## Details 

- Document the new `contentSourcePath` property on `DeliveryConfig` in
the OpenAPI spec.
- This field stores the AEM content root path and is used to
disambiguate sites sharing a Cloud Manager program/environment.


Thanks for contributing!

---------

Co-authored-by: Radhika Gupta <radhikagupta@Radhikas-MacBook-Pro-2.local>
Co-authored-by: Ben Helleman <bhellema@adobe.com>

Author: 3 people

docs/index.html

@@ -128,6 +128,12 @@ DeliveryConfig:
       description: The site ID
       type: string
       example: '1234'
+    contentSourcePath:
+      description: >-
+        AEM content root path for a site. Corresponds to `/content/<site-name>` in the AEM repository.
+        Used to disambiguate multiple sites that share the same Cloud Manager program and environment.
+      type: string
+      example: '/content/aboutus'
   additionalProperties: true
 AuditType:
   type: string