Hide spell-check settings if not using Electron

src/BasePlatform.ts

@@ -128,6 +128,14 @@ export default abstract class BasePlatform {
         hideUpdateToast();
     }
 
+    /**
+     * Return true if platform supports multi-language
+     * spell-checking, otherwise false.
+     */
+    supportsMultiLanguageSpellCheck(): boolean {
+        return false;
+    }
+
     /**
      * Returns true if the platform supports displaying
      * notifications, otherwise false.