extensions/typescript-language-features/src/languageProvider.ts/LanguageProvider/documentSelector
class LanguageProvider:	private get documentSelector(): DocumentSelector {
		const semantic: vscode.DocumentFilter[] = [];
		const syntax: vscode.DocumentFilter[] = [];
		for (const language of this.description.languageIds) {
			syntax.push({ language });
			for (const scheme of fileSchemes.semanticSupportedSchemes) {
				semantic.push({ language, scheme });
			}
		}

		return { semantic, syntax };
	}