Use Angle Bracket Links

Co-authored-by: Eric Huss <[email protected]>

Author: Havvy

src/introduction.md

@@ -23,9 +23,9 @@ Tools (`rustc`, `cargo`, etc.) and documentation ([Standard library], this book,
 
 While tools often have the same version as the Rust language, the language exists as its own concept separately from them.
 
-The latest release of this book, matching the latest Rust version, can always be found at [https://doc.rust-lang.org/reference/](https://doc.rust-lang.org/reference/).
+The latest release of this book, matching the latest Rust version, can always be found at <https://doc.rust-lang.org/reference/>.
 Prior versions can be found by adding the Rust version before the "reference" directory.
-For example, the Reference for Rust 1.49.0 is located at [https://doc.rust-lang.org/1.49.0/reference/](https://doc.rust-lang.org/1.49.0/reference/).
+For example, the Reference for Rust 1.49.0 is located at <https://doc.rust-lang.org/1.49.0/reference/>.
 
 ## What *The Reference* is Not