Error handling: Rename renderers to formatters

Refs #1641.

src/Foundation/ErrorHandling/HttpFormatter.php

@@ -14,7 +14,7 @@ namespace Flarum\Foundation\ErrorHandling;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-interface Formatter
+interface HttpFormatter
 {
     public function format(HandledError $error, Request $request): Response;
 }

src/Foundation/ErrorHandling/JsonApiFormatter.php

@@ -16,7 +16,7 @@ use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 use Tobscure\JsonApi\Document;
 
-class JsonApiRenderer implements Formatter
+class JsonApiFormatter implements HttpFormatter
 {
     public function format(HandledError $error, Request $request): Response
     {

src/Foundation/ErrorHandling/ViewFormatter.php

@@ -18,7 +18,7 @@ use Psr\Http\Message\ServerRequestInterface as Request;
 use Symfony\Component\Translation\TranslatorInterface;
 use Zend\Diactoros\Response\HtmlResponse;
 
-class ViewRenderer implements Formatter
+class ViewFormatter implements HttpFormatter
 {
     /**
      * @var ViewFactory

src/Foundation/ErrorHandling/WhoopsFormatter.php

@@ -15,7 +15,7 @@ use Franzl\Middleware\Whoops\WhoopsRunner;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class WhoopsRenderer implements Formatter
+class WhoopsFormatter implements HttpFormatter
 {
     public function format(HandledError $error, Request $request): Response
     {