fix review stuff

Author: steveklabnik

_posts/2018-01-04-Rust-1.23.md

@@ -23,9 +23,10 @@ appropriate page on our website, and check out the [detailed release notes for
 
 ## What's in 1.23.0 stable
 
-New year, new Rust! For our first improvement today, we now [avoid some uneccesary
+New year, new Rust! For our first improvement today, we now [avoid some unnecessary
 copies](https://github.com/rust-lang/rust/pull/45380) in certain situations.
-We've seen memory usage drop 5-10% with this change.
+We've seen memory usage of using `rustc` to drop 5-10% with this change; it may
+be different with your programs.
 
 The documentation team has been on a long journey to move `rustdoc` to use
 [CommonMark]. Previously, `rustdoc` never guaranteed which markdown rendering
@@ -80,19 +81,19 @@ to import the trait. Thanks to our stability guarantees, this trait still exists
 like to still support Rust versions before Rust 1.23, you can do this:
 
 ```rust
-#[warn(unused_imports)]
+#[allow(unused_imports)]
 use std::ascii::AsciiExt;
 ```
 
-To supress the related warning. Once you drop support for older Rusts, you
+…to suppress the related warning. Once you drop support for older Rusts, you
 can remove both lines, and everything will continue to work.
 
 [`AsciiExt`]: https://doc.rust-lang.org/std/ascii/trait.AsciiExt.html
 
 Additionally, a few new APIs were stabilized this release:
 
 * The various [`std::sync::atomic
-  types`](https://doc.rust-lang.org/beta/std/sync/atomic/index.html#structs)
+  types`](https://doc.rust-lang.org/std/sync/atomic/index.html#structs)
   now implement `From` their non-atomic types. For example, `let x = AtomicBool::from(true);`.
 * [`()` now implements `FromIterator<()>`](https://github.com/rust-lang/rust/pull/45379); check the PR for
   a neat use-case.