Rollup merge of rust-lang#160836 - Jontos:fix-read-doc-line-order, r=nia-e

Fix swapped documentation lines on `io::Read`

While reading the documentation for the `std::io::Read` trait, I noticed some wording out of order:
> Please note that each call to [read()](https://doc.rust-lang.org/nightly/std/io/trait.Read.html#method.read) may involve a system call, and BufReader, will be more efficient. therefore, using something that implements [BufRead](https://doc.rust-lang.org/nightly/std/io/trait.BufRead.html), such as

It looks like rust-lang#158546 accidentally swapped two lines when inserting an intra-doc link; this PR swaps them back.

Author: JonathanBrouwer

library/alloc/src/io/read.rs

@@ -22,8 +22,8 @@ use crate::vec::Vec;
 /// trait.
 ///
 /// Please note that each call to [`read()`] may involve a system call, and
-/// `BufReader`, will be more efficient.
 /// therefore, using something that implements [`BufRead`], such as
+/// `BufReader`, will be more efficient.
 ///
 /// [`BufRead`]: crate::io::BufRead
 ///