Since xenForo 2.0.1 release you can add additional language support on your forum. There was no way to do so before due to this bug.
This method of adding additional language was proposed by @Chris D.
In this example, I will be adding LaTeX support.
1. Downloading PrismJS components
@Chris D suggested that I post a suggestion here. (I found one already so I just second the motion but found it's under closed suggestion due to lack of interest)
Since XF2 has now increased support of numbers of coding languages, it makes sense for include latex since it's a language...