Make language switch show current language

Author: akudev

assets/js/custom.js

@@ -221,6 +221,7 @@ function createLanguageButton(text, lang) {
 	const button = document.createElement("button");
 	button.textContent = text;
 	button.classList.add("language-switch-button");
+	button.classList.add("lang-" + lang);
 	button.addEventListener("click", () => switchLanguage(lang));
 	return button;
 }