update from tracking issue

Author: devnexen

library/std/src/os/unix/net/stream.rs

@@ -454,16 +454,27 @@ impl UnixStream {
     /// Set a filter name on the socket to filter incoming connections to defer it before accept(2)
     ///
     /// an empty name allows to remove this connection's filter
+    #[cfg_attr(any(target_os = "freebsd", target_os = "netbsd"), doc = "```no_run")]
+    #[cfg_attr(not(any(target_os = "freebsd", target_os = "netbsd")), doc = "```ignore")]
+    /// #![feature(unix_set_mark)]
+    /// use std::os::unix::net::UnixStream;
+    ///
+    /// fn main() -> std::io::Result<()> {
+    ///     let sock = UnixStream::connect("/tmp/sock")?;
+    ///     sock.set_acceptfilter(&c"http")?;
+    ///     Ok(())
+    /// }
+    /// ```
     #[cfg(any(doc, target_os = "netbsd", target_os = "freebsd"))]
-    #[unstable(feature = "acceptfilter", issue = "none")]
+    #[unstable(feature = "acceptfilter", issue = "121891")]
     pub fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
         self.0.set_acceptfilter(name)
     }
 
     /// Get a filter name if one had been set previously on the socket.
     ///
     #[cfg(any(doc, target_os = "netbsd", target_os = "freebsd"))]
-    #[unstable(feature = "acceptfilter", issue = "none")]
+    #[unstable(feature = "acceptfilter", issue = "121891")]
     pub fn acceptfilter(&self) -> io::Result<&CStr> {
         self.0.acceptfilter()
     }