Enable page-feedback form for doc pages (#4772)

hugo.yaml

@@ -95,7 +95,15 @@ params:
     sidebar_menu_compact: true
     sidebar_menu_foldable: true
     sidebar_search_disable: true
-
+    feedback:
+      enable: true
+      'yes': >-
+        Thank you. Your feedback is appreciated!
+      # prettier-ignore
+      'no': >-
+        Please let us know <a class="external-link" target="_blank" rel="noopener"
+        href="https://github.com/open-telemetry/opentelemetry.io/issues/new?title=Page%20feedback&body=Suggested%20improvements%20for%20page:%20ADD%20PAGE-URL-HERE">how
+        we can improve this page</a>. Your feedback is appreciated!
   links:
     user:
       - name: Mailing Lists