fix link

Author: steveklabnik

_posts/2017-07-20-Rust-1.19.md

@@ -140,7 +140,7 @@ The largest new library feature is the [`eprint!` and `eprintln!` macros].
 These work exactly the same as `print!` and `printn!`, but instead write
 to standard error, as opposed to standard output.
 
-[`eprint!` and `eprintln!` macros]: [41192]: https://github.com/rust-lang/rust/pull/41192
+[`eprint!` and `eprintln!` macros]: https://github.com/rust-lang/rust/pull/41192
 
 Other new features: