src/vs/editor/common/services/languagesRegistry.ts/LanguagesRegistry/_registerLanguage
class LanguagesRegistry:	private _registerLanguage(lang: ILanguageExtensionPoint): void {
		const langId = lang.id;

		let resolvedLanguage: IResolvedLanguage;
		if (hasOwnProperty.call(this._languages, langId)) {
			resolvedLanguage = this._languages[langId];
		} else {
			this.languageIdCodec.register(langId);
			resolvedLanguage = {
				identifier: langId,
				name: null,
				mimetypes: [],
				aliases: [],
				extensions: [],
				filenames: [],
				configurationFiles: [],
				icons: []
			};
			this._languages[langId] = resolvedLanguage;
		}

		this._mergeLanguage(resolvedLanguage, lang);
	}