Fix docs for MacOs (correction)

Author: LinkTed

library/std/src/sys/unix/ext/net/stream.rs

@@ -364,7 +364,8 @@ impl UnixStream {
     ///
     /// # Examples
     ///
-    /// ```no_run
+    #[cfg_attr(any(target_os = "android", target_os = "linux"), doc = "```no_run")]
+    #[cfg_attr(not(any(target_os = "android", target_os = "linux")), doc = "```ignore")]
     /// #![feature(unix_socket_ancillary_data)]
     /// use std::os::unix::net::UnixStream;
     ///