Removed the marked language prefix of `lang-`
Removed the marked language prefix of `lang-`

The purpose for this was that highlight.js' default styling only styled
for `markdown` instead of `lang-markdown`. This may not be the best
workaround, but i don't believe there are any downsides currently.

mehulsbhatt/kdlearn,koding/kdlearn,jormaral/kdlearn,jdloft/kdlearn