refactor!: replace pack! macros with derive-based pipeline types

Remove the `pack!`, `pack_err!`, `pack_structural!`, and
`pack_err_structural!` macros, replacing all pipeline type definitions
with `#[derive(Grouped)]` and `#[derive(Grouped, Wrap)]` attributes.
This changes the generated struct shape from named-field structs with an
`inner` field to tuple structs accessed via `.0`, and removes the
auto-generated `name` and `info` fields from error types.

1 files changed, 3 insertions, 2 deletions

diff --git a/examples/example-async-support/src/main.rs b/examples/example-async-support/src/main.rs
index 090602a..7e212d9 100644
--- a/examples/example-async-support/src/main.rs
+++ b/examples/example-async-support/src/main.rs
@@ -41,7 +41,8 @@ async fn main() {
 
 dispatcher!("download", EntryDownload);
 
-pack!(ResultDownloaded = String);
+#[derive(Grouped, Wrap)]
+pub struct ResultDownloaded(String);
 
 // --------- IMPORTANT ---------
 #[chain]
@@ -65,5 +66,5 @@ gen_program!();
 
 async fn fake_download(file_name: String) -> ResultDownloaded {
     tokio::time::sleep(std::time::Duration::from_secs(1)).await;
-    ResultDownloaded::new(file_name)
+    ResultDownloaded(file_name)
 }