Use @generated in files created by

frb_codegen/src/library/codegen/generator/misc/mod.rs

@@ -36,7 +36,7 @@ pub fn is_js_value(ty: &MirType) -> bool {
 pub(crate) fn generate_code_header() -> String {
     format!(
         "// This file is automatically generated, so please do not edit it.
-// Generated by `flutter_rust_bridge`@ {}.",
+// @generated by `flutter_rust_bridge`@ {}.",
         env!("CARGO_PKG_VERSION")
     )
 }