Fix merge request types handbook link

danger/documentation/Dangerfile

@@ -70,7 +70,7 @@ DOCUMENTATION_UPDATE_MISSING = <<~MSG
 
 For more information, see:
 
-- The Handbook page on [merge request types](https://about.gitlab.com/handbook/engineering/metrics/#work-type-classification).
+- The Handbook page on [merge request types](https://handbook.gitlab.com/handbook/product/groups/product-analysis/engineering/metrics/#work-type-classification).
 - The [definition of done](https://docs.gitlab.com/ee/development/contributing/merge_request_workflow.html#definition-of-done) documentation.
 MSG