Update src/libcore/option.rs

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

Author: Dolpheyn

src/libcore/option.rs

@@ -1357,7 +1357,7 @@ impl<'a, T> IntoIterator for &'a mut Option<T> {
 
 #[stable(since = "1.12.0", feature = "option_from")]
 impl<T> From<T> for Option<T> {
-    /// Copies val to a new Option::Some
+    /// Copies `val` into a new `Some`.
     ///
     /// # Examples
     ///