Fix external writeup link

Author: defund

reverse-engineering/67k-400-points.md

@@ -140,7 +140,7 @@ So it looks like the binaries will create some obfuscated Javascript code, speci
 
 * [https://github.com/VulnHub/ctf-writeups/blob/master/2017/easyctf/67k.md](https://github.com/VulnHub/ctf-writeups/blob/master/2017/easyctf/67k.md)
 * [https://www.youtube.com/watch?v=7AB6Nx9\_K6A](https://www.youtube.com/watch?v=7AB6Nx9_K6A)
-* [https://defund.io/post/easyctf-2017-writeups/](defund's writeup)
+* [defund's writeup](https://defund.io/post/easyctf-2017-writeups/)