Update src/libcore/option.rs

Co-authored-by: Steve Klabnik <steve@steveklabnik.com>

Author: Dolpheyn

src/libcore/option.rs

@@ -1376,6 +1376,7 @@ impl<'a, T> From<&'a Option<T>> for Option<&'a T> {
     /// Converts from `&Option<T>` to `Option<&T>`.
     ///
     /// # Examples
+    ///
     /// Converts an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, preserving the original.
     /// The [`map`] method takes the `self` argument by value, consuming the original,
     /// so this technique uses `as_ref` to first take an `Option` to a reference