apply havvy nits

Author: nikomatsakis

src/expressions/await-expr.md

@@ -11,7 +11,7 @@ to produce a value.
 
 More specifically, an `<expr>.await` expression has the following effect.
 
-1. Evaluate `<expr>` to a future `tmp`;
+1. Evaluate `<expr>` to a [future] `tmp`;
 2. Pin `tmp` using `Pin::new_unchecked`;
 3. This pinned future is then polled by calling the [`Future::poll`] method and
    passing it the current task context (see below);
@@ -23,6 +23,7 @@ More specifically, an `<expr>.await` expression has the following effect.
    value contained in the [`Poll::Ready`] variant is used as the result
    of the `await` expression itself.
 
+[future]: https://doc.rust-lang.org/std/future/trait.Future.html
 [_Expression_]: expressions.html
 [`Future::poll`]: https://doc.rust-lang.org/std/future/trait.Future.html#tymethod.poll
 [`Context`]: https://doc.rust-lang.org/std/task/struct.Context.html
@@ -34,9 +35,9 @@ More specifically, an `<expr>.await` expression has the following effect.
 ## Task context
 
 The task context refers to the [`Context`] which was supplied to the
-current [async context] when it itself was polled. Because `await`
-expressions are only legal in an async context, there must be some
-task context available.
+current [async context] when the async context itself was
+polled. Because `await` expressions are only legal in an async
+context, there must be some task context available.
 
 [`Context`]: https://doc.rust-lang.org/std/task/struct.Context.html
 [async context]: ../expressions/block-expr.html#async-context

src/expressions/block-expr.md

@@ -95,9 +95,11 @@ its immediate effect is to produce and return an anonymous type.
 Whereas closures return a type that implements one or more of the
 `std::ops::Fn` traits, however, the type returned for an async block
 implements the `std::future::Future` trait. The actual data format for
-this type is unspecified, but it is roughly equivalent to an enum with
-one variant per `await` point, where each variant stores the data
-needed to resume from its corresponding point.
+this type is unspecified.
+
+> **Note:** The future type that rustc generates is roughly equivalent
+> to an enum with one variant per `await` point, where each variant
+> stores the data needed to resume from its corresponding point.
 
 > **Edition differences**: Async blocks are only available in Rust 2018.