fix docs (#967)

crates/proxy/src/lib.rs

@@ -4,7 +4,7 @@
 //!
 //! In this example, if the requested URL begins with <http://127.0.0.1:5800/>, the proxy goes to
 //! <https://www.rust-lang.org>; if the requested URL begins with <http://localhost:5800/>, the proxy
-//! goes to <https://www.rust-lang.org>.
+//! goes to <https://crates.io>.
 //!
 //! ```no_run
 //! use salvo_core::prelude::*;