ci: revert the readthedocs trigger back to template

.github/workflows/documentation-links.yml

@@ -1,14 +1,12 @@
 name: readthedocs preview
 on:
-  pull_request:
-    branches: [ "main" ]
-  # pull_request_target:
-  #   types:
-  #     - opened
-  #   # Execute this action only on PRs that touch
-  #   # documentation files.
-  #   # paths:
-  #   #   - "docs/**"
+  pull_request_target:
+    types:
+      - opened
+    # Execute this action only on PRs that touch
+    # documentation files.
+    # paths:
+    #   - "docs/**"
 
 permissions:
   pull-requests: write