Merge pull request #1392 from ejez/patch-1

Update old invalid link

src/error/option_unwrap/map.md

@@ -80,7 +80,7 @@ fn main() {
 
 [closures][closures], [`Option`][option], [`Option::map()`][map]
 
-[combinators]: https://doc.rust-lang.org/book/glossary.html#combinators
+[combinators]: https://doc.rust-lang.org/reference/glossary.html#combinator
 [closures]: ../../fn/closures.md
 [option]: https://doc.rust-lang.org/std/option/enum.Option.html
 [map]: https://doc.rust-lang.org/std/option/enum.Option.html#method.map