Rollup merge of rust-lang#58600 - llogiq:documentation-tests-typo, r=frewsxcv

fix small documentation typo

Thanks to @stjepang for catching my mistake.

Author: Centril

src/doc/rustdoc/src/documentation-tests.md

@@ -244,7 +244,7 @@ disambiguate the error type:
 /// use std::io;
 /// let mut input = String::new();
 /// io::stdin().read_line(&mut input)?;
-/// # Ok::<(), io:Error>(())
+/// # Ok::<(), io::Error>(())
 /// ```
 ```