message: docs: update link to plugins/graphql-backend
diff: @@ -279,7 +279,7 @@ Integrates GraphiQL as a tool to browse GraphQL API endpoints inside Backstage.
  Stability: `1`
  -### `graphql` [GitHub](https://github.com/backstage/backstage/tree/master/plugins/graphql/)
  +### `graphql` [GitHub](https://github.com/backstage/backstage/tree/master/plugins/graphql-backend/)
  A backend plugin that provides
  