Add todo about adding error inside CreateWindow

Author: Legend-Master

crates/tauri-runtime/src/lib.rs

@@ -126,6 +126,7 @@ pub enum Error {
   /// Failed to create webview.
   #[error("failed to create webview: {0}")]
   CreateWebview(Box<dyn std::error::Error + Send + Sync>),
+  // TODO: Make it take an error like `CreateWebview` in v3
   /// Failed to create window.
   #[error("failed to create window")]
   CreateWindow,