minor symfony#24618 content can be a resource (DQNEO)

This PR was merged into the 2.7 branch.

Discussion
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content can be a resource

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes (bug in a comment)
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Commits
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c63742d content can be a resource

Author: fabpot

src/Symfony/Component/HttpFoundation/Request.php

@@ -130,7 +130,7 @@ class Request
     public $headers;
 
     /**
-     * @var string
+     * @var string|resource
      */
     protected $content;