function loadPrismLang(lang) {
    if (!lang) return undefined;
    let langObject = Prism.languages[lang];
    if (langObject === undefined) {
        try {
            require('prismjs/components/index')([lang]);
            return Prism.languages[lang];
        } catch (e) {
            // nothing to do
        }
    }
    return langObject;
}
Loads the provided {@code lang} into prism.

@param {String} lang
       Code of the language to load.
@return {Object} The Prism language object for the provided {@code lang} code. {@code undefined} if the language is not known to Prism.