Skip lio_listio doc test on musl/aarch64/i686 as it hangs

Do not run this doc test on:

* aarch64-unknown-linux-musl
* i686-unknown-linux-musl

because it hangs on these targets. After further debugging, we think this is
likely a bug of musl. Since we only test our bindings and do not intend to
fix the underlying libc bug, we skip this test here. See this thread [1] for
the discussion of this issue

[1]: #2689 (comment)

Author: SteveLauC

src/sys/aio.rs

@@ -1141,7 +1141,17 @@ pub fn aio_suspend(
 /// `EINTR`, in which case some but not all operations may have been submitted.
 /// In that case, you must check the status of each individual operation, and
 /// possibly resubmit some.
-/// ```
+/// 
+// Do not run this doc test on:
+//   * aarch64-unknown-linux-musl
+//   * i686-unknown-linux-musl
+// because it hangs on these targets. After further debugging, we think this is
+// likely a bug of musl. Since we only test our bindings and do not intend to 
+// fix the underlying libc bug, we skip this test here.
+// See this thread for the discussion of this issue:
+// https://github.com/nix-rust/nix/pull/2689#issuecomment-3419813159
+#[cfg_attr(all(target_env = "musl", any(target_arch = "aarch64", target_arch = "x86")), doc = " ```no_run")]
+#[cfg_attr(not(all(target_env = "musl", any(target_arch = "aarch64", target_arch = "x86"))), doc = " ```")]
 /// # use libc::c_int;
 /// # use std::os::unix::io::AsFd;
 /// # use std::sync::atomic::{AtomicBool, Ordering};