fix(tvix/nix-compat): async nar reader requires wire feature

It uses it internally.

Change-Id: I8cb8fc9f567260d57f3a203407333d83beddf537
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11719
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

tvix/nix-compat/src/nar/reader/mod.rs

@@ -16,7 +16,7 @@ use std::marker::PhantomData;
 // Required reading for understanding this module.
 use crate::nar::wire;
 
-#[cfg(feature = "async")]
+#[cfg(all(feature = "async", feature = "wire"))]
 pub mod r#async;
 
 mod read;