fix(graphql): docs should answer text/html

Author: soyuka

features/graphql/docs.feature

@@ -0,0 +1,10 @@
+Feature: Documentation support
+ In order to play with GraphQL
+ As a client software developer
+ I want to reach the GraphQL documentation
+
+ Scenario: Retrieve the OpenAPI documentation
+ Given I add "Accept" header equal to "text/html"
+ And I send a "GET" request to "/graphql"
+ Then the response status code should be 200
+ And the header "Content-Type" should be equal to "text/html; charset=utf-8"

src/GraphQl/Action/GraphQlPlaygroundAction.php

@@ -37,7 +37,7 @@ public function __invoke(Request $request): Response
  'title' => $this->title,
  'graphql_playground_data' => ['entrypoint' => $this->router->generate('api_graphql_entrypoint')],
  'assetPackage' => $this->assetPackage,
- ]));
+ ]), 200, ['content-type' => 'text/html']);
  }
 
  throw new BadRequestHttpException('GraphQL Playground is not enabled.');

src/GraphQl/Action/GraphiQlAction.php

@@ -37,7 +37,7 @@ public function __invoke(Request $request): Response
  'title' => $this->title,
  'graphiql_data' => ['entrypoint' => $this->router->generate('api_graphql_entrypoint')],
  'assetPackage' => $this->assetPackage,
- ]));
+ ]), 200, ['content-type' => 'text/html']);
  }
 
  throw new BadRequestHttpException('GraphiQL is not enabled.');