fix the hacking tutorials

Medium/31.md

@@ -149,7 +149,7 @@ From there all that we have to do is upload our reverse php shell and use it to
       → nano nihilist.php
     
 
-Now the trick here is, we are not on a Linux box like on [Apocalyst](11.html), we need to tweak our reverse php shell like so : 
+Now the trick here is, we are not on a Linux box like on [Apocalyst](11.md), we need to tweak our reverse php shell like so : 
     
     
       <****?php