Create type definition for 'langmap' (#4059)

* Create type definition for 'langmap'

* Follow lint

src/@types/langmap.d.ts

@@ -0,0 +1,10 @@
+declare module 'langmap' {
+	type Lang = {
+		nativeName: string;
+		englishName: string;
+	};
+
+	const langmap: { [lang: string]: Lang };
+
+	export = langmap;
+}

src/server/api/endpoints/i/update.ts

@@ -9,7 +9,7 @@ import getDriveFileUrl from '../../../../misc/get-drive-file-url';
 import { parse, parsePlain } from '../../../../mfm/parse';
 import extractEmojis from '../../../../misc/extract-emojis';
 import extractHashtags from '../../../../misc/extract-hashtags';
-const langmap = require('langmap');
+import * as langmap from 'langmap';
 
 export const meta = {
 	desc: {