chore: Fix link in explanation page

docs/explanations/cloud-platform/aws.md

@@ -65,7 +65,7 @@ IAM Role.
 
 As our use of AWS is rare, we'd like to avoid having to develop an entire parallel permissions
 model. The model we use with Google Cloud is explained [in a separate
-guide](./google-cloud-permissions-model) but in brief:
+guide](./google-cloud-permissions-model.md) but in brief:
 
 - Real Person "admin" users sign in to Google with [gcloud admin
   accounts](site:howtos/cloud-platform/create-gcloudadmin-account) which are managed by the