Merge branch 'docs/280'

Close #280

Author: michalbundyra

docs/book/validators/file/upload.md

@@ -8,7 +8,7 @@ successful.
 `Zend\Validator\File\Upload` supports the following options:
 
 - `files`: array of file uploads. This is generally the `$_FILES` array, but
-  should be normalized per the details in [PSR-7](http://www.php-fig.org/psr/psr-7/#1-6-uploaded-files)
+  should be normalized per the details in [PSR-7](http://www.php-fig.org/psr/psr-7/#16-uploaded-files)
   (which is also how [the zend-http Request](https://docs.zendframework.com/zend-http)
   normalizes the array).