use localized placeholder values for text input fields

assets/launch.js

@@ -91,6 +91,19 @@ function applyTranslations() {
         element.textContent = value;
       }
     });
+
+  /*
+   * Platzhalter von Eingabefeldern übersetzen.
+   */
+  document
+    .querySelectorAll("[data-i18n-placeholder]")
+    .forEach((element) => {
+      const value = getTranslation(element.dataset.i18nPlaceholder);
+
+      if (value !== null) {
+        element.placeholder = value;
+      }
+    });
 }
 
 /*