Add PR link to NEXT_CHANGELOG entry per contribution guidelines

Co-authored-by: Isaac

Author: airizarryDB

NEXT_CHANGELOG.md

@@ -8,7 +8,9 @@
 
 ### New Features and Improvements
 
- * Added `user_agent_extra` provider configuration attribute to append products to the `User-Agent` header, equivalent to the `DATABRICKS_USER_AGENT_EXTRA` environment variable. This lets Terraform modules built on top of the provider configure usage attribution in their `provider` block without requiring users to set environment variables.
+ * Added `user_agent_extra` provider configuration attribute to append products to the `User-Agent` header, equivalent to the `DATABRICKS_USER_AGENT_EXTRA` environment variable ([#5863](https://github.com/databricks/terraform-provider-databricks/pull/5863)).
+
+   This lets Terraform modules built on top of the provider configure usage attribution in their `provider` block without requiring users to set environment variables.
 
 ### Bug Fixes