Update index.html

There was a short error on one of your pseudocodes. I just thought that i would correct it as I was a bit puzzled when I saw it.

Regards
Ashley Hammond (7E)
Merge pull request #1 from AshHam/master

Update index.html - 'Arriving at the router' Pseudocode
yt fix
Merge branch 'master' of https://github.com/MarcScott/How_the_internet_works
Merge branch 'master' into gh-pages