Translate change-language.js

[DeAlexPesh]

Add please prefix

const [languagesResponse, currentLanguageResponse] = await Promise.all([  
-    fetch('/get-languages'),  
-    fetch('/get-locale') 
+    fetch(`${url_prefix}/get-languages`),  
+    fetch(`${url_prefix}/get-locale`) 
]);  

function changeLanguage(lang) {  
-    fetch("/change-language", { 
+    fetch(`${url_prefix}/change-language`, { 

And add please normal naming

en_US -> English
etc.

[Ramon]

Ty