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-setup/src/main.rs b/examples/example-setup/src/main.rs
index 523a567..59c503f 100644
--- a/examples/example-setup/src/main.rs
+++ b/examples/example-setup/src/main.rs
@@ -55,13 +55,14 @@ fn custom_setup(program: &mut Program<ThisProgram>) {
 
 dispatcher!("greet", EntryGreet);
 
-pack!(ResultGreeting = String);
+#[derive(Grouped, Wrap)]
+pub struct ResultGreeting(String);
 
 /// Chain: reads the `ResAppName` and `ResAppVersion` resources.
 #[chain]
 fn handle_greet(args: EntryGreet, app: &ResAppName, version: &ResAppVersion) -> Next {
     let who = args
-        .inner
+        .0
         .first()
         .cloned()
         .unwrap_or_else(|| "World".to_string());