Update libcore implementation links

Author: dtolnay

README.md

@@ -12,7 +12,7 @@ penalty of going through [`core::fmt::Formatter`].
 
 See also [`ryu`] for printing floating point primitives.
 
-[libcore]: https://github.com/rust-lang/rust/blob/b8214dc6c6fc20d0a660fb5700dca9ebf51ebe89/src/libcore/fmt/num.rs#L201-L254
+[libcore]: https://github.com/rust-lang/rust/blob/1.92.0/library/core/src/fmt/num.rs#L190-L253
 [`core::fmt::Formatter`]: https://doc.rust-lang.org/std/fmt/struct.Formatter.html
 [`ryu`]: https://github.com/dtolnay/ryu
 

src/lib.rs

@@ -12,7 +12,7 @@
 //!
 //! See also [`ryu`] for printing floating point primitives.
 //!
-//! [libcore]: https://github.com/rust-lang/rust/blob/b8214dc6c6fc20d0a660fb5700dca9ebf51ebe89/src/libcore/fmt/num.rs#L201-L254
+//! [libcore]: https://github.com/rust-lang/rust/blob/1.92.0/library/core/src/fmt/num.rs#L190-L253
 //! [`ryu`]: https://github.com/dtolnay/ryu
 //!
 //! # Example