docs(elicit_tokio): fix broken intra-doc link on Windows

TokioUnixPlugin is cfg(unix) so the link resolves on Linux/macOS
but breaks on Windows with -D warnings. Use plain code text instead.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: crumplecup

crates/elicit_tokio/src/lib.rs

@@ -21,7 +21,7 @@
 //! | [`TokioSignalPlugin`] | `tokio_signal__*` | ctrl_c, unix_signal_create (unix), unix_signal_recv (unix), unix_signal_close (unix) |
 //! | [`TokioIoPlugin`] | `tokio_io__*` | duplex_create, duplex_read, duplex_write, duplex_close |
 //! | [`TokioIoCopyPlugin`] | `tokio_io_copy__*` | one dynamic tool per registered `(R, W)` pair |
-//! | [`TokioUnixPlugin`] | `tokio_unix__*` | unix_listener_bind, unix_listener_accept, unix_listener_local_addr, unix_listener_close, unix_stream_connect, unix_stream_read, unix_stream_write, unix_stream_local_addr, unix_stream_peer_addr, unix_stream_close, unix_datagram_bind, unix_datagram_send_to, unix_datagram_recv_from, unix_datagram_local_addr, unix_datagram_close (**unix only**) |
+//! | `TokioUnixPlugin` | `tokio_unix__*` | unix_listener_bind, unix_listener_accept, unix_listener_local_addr, unix_listener_close, unix_stream_connect, unix_stream_read, unix_stream_write, unix_stream_local_addr, unix_stream_peer_addr, unix_stream_close, unix_datagram_bind, unix_datagram_send_to, unix_datagram_recv_from, unix_datagram_local_addr, unix_datagram_close (**unix only**) |
 //!
 //! # Feature flags
 //!