feat(ts): added export for languages in types declaration file

Author: CorentinTh

src/index.d.ts

@@ -229,6 +229,9 @@ declare namespace Tesseract {
     pdf: number[] | null;
     debug: string | null;
   }
+  const languages: {
+    [key: string]: string;
+  };
 }
 
 export = Tesseract;