Updated help about symlinks and hardlinks

It now mentions that Windows is supported and under which
conditions it is. Ref #220.

help/en/results.rst

@@ -135,7 +135,12 @@ any of them.
   wikipedia pages about them to make a informed choice, but in short, a symlink is a shortcut to
   the file's path. If the original file is deleted or moved, the link is broken. A hardlink is a
   link to the file *itself*. That link is as good as a "real" file. Only when *all* hardlinks to a
-  file are deleted is the file itself deleted. (Only for OS X and Linux)
+  file are deleted is the file itself deleted.
+
+  On OSX and Linux, this feature is supported fully, but under Windows, it's a bit complicated.
+  Windows XP doesn't support it, but Vista and up support it. However, for the feature to work,
+  dupeGuru has to run with administrative privileges.
+
 * **Directly delete files:** Instead of sending files to trash, directly delete them. This is used
   for troubleshooting and you normally don't need to enable this unless dupeGuru has problems
   deleting files normally, something that can happens when you try to delete files on network