[6.x] Update Filesystem::link documentation (#31184)

* Update Filesystem::link documentation

The method creates symlink on Unixes and hard links on windows.

* Update Filesystem.php

Co-authored-by: Taylor Otwell <taylor@laravel.com>

src/Illuminate/Filesystem/Filesystem.php

@@ -251,7 +251,7 @@ public function copy($path, $target)
     }
 
     /**
-     * Create a hard link to the target file or directory.
+     * Create a symlink to the target file or directory. On Windows, a hard link is created if the target is a file.
      *
      * @param  string  $target
      * @param  string  $link