fix: update builtin command mapping

src/builtins/mod.rs

@@ -32,7 +32,7 @@ const BUILTINS: Lazy<Vec<(&str, Box<dyn Builtin>)>> = Lazy::new(|| {
         ("exit", Box::new(exit::Exit)),
         ("pwd", Box::new(pwd::Pwd)),
         ("open", Box::new(open::Open)),
-        ("fetch", Box::new(open::Open)),
+        ("fetch", Box::new(fetch::Fetch)),
     ]
 });