Remove blank lines in AsRef documentation

Author: czipperz

src/libcore/convert.rs

@@ -104,7 +104,6 @@ pub const fn identity<T>(x: T) -> T { x }
 /// If you need to do a costly conversion it is better to implement [`From`] with type
 /// `&T` or write a custom function.
 ///
-///
 /// `AsRef` has the same signature as [`Borrow`], but `Borrow` is different in few aspects:
 ///
 /// - Unlike `AsRef`, `Borrow` has a blanket impl for any `T`, and can be used to accept either
@@ -149,7 +148,6 @@ pub const fn identity<T>(x: T) -> T { x }
 /// let s = "hello".to_string();
 /// is_hello(s);
 /// ```
-///
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsRef<T: ?Sized> {
     /// Performs the conversion.