Update PHPDoc

admin/src/Admin.php

@@ -90,7 +90,7 @@ class Admin
     }
 
     /**
-     * Return whether some user is logged in
+     * Return whether a user is logged in
      *
      * @return bool
      */

admin/src/Updater.php

@@ -61,7 +61,7 @@ class Updater
     /**
      * Headers to send in HTTP(S) requests
      *
-     * @var array
+     * @var array|null
      */
     protected $headers;
 

formwork/Utils/FileSystem.php

@@ -77,7 +77,7 @@ class FileSystem
      *
      * @param string $file
      *
-     * @return array|string
+     * @return string|null
      */
     public static function mimeType($file)
     {

formwork/Utils/MimeType.php

@@ -80,7 +80,7 @@ class MimeType
      *
      * @param string $extension
      *
-     * @return array|null
+     * @return string|null
      */
     public static function fromExtension($extension)
     {