Add missing PHPdoc return types

Author: wouterj

HeaderBag.php

@@ -254,6 +254,9 @@ public function count(): int
         return \count($this->headers);
     }
 
+    /**
+     * @return string
+     */
     protected function getCacheControlHeader()
     {
         ksort($this->cacheControl);

ResponseHeaderBag.php

@@ -55,6 +55,9 @@ public function allPreserveCase(): array
         return $headers;
     }
 
+    /**
+     * @return array
+     */
     public function allPreserveCaseWithoutCookies()
     {
         $headers = $this->allPreserveCase();
@@ -224,6 +227,8 @@ public function clearCookie(string $name, ?string $path = '/', string $domain =
 
     /**
      * @see HeaderUtils::makeDisposition()
+     *
+     * @return string
      */
     public function makeDisposition(string $disposition, string $filename, string $filenameFallback = '')
     {