Add ability to show language for code as a title

[CharlieGreenman]

I could be wrong but I believe it's show-language, so add a show language feature

"node_modules/prismjs/plugins/show-language/prism-show-language.min.js",

I can also make a pull request for this, if you think it's a good idea. Thank you

[Luxcy]

How to implement the code？