Revise Registry comments and examples
Removed `MyActor1.start()` from the SystemRegistry example, as there
would otherwise be two MyActor1's running (since MyActor2 starts a
MyActor1 when it tries to get MyActor1 from the registry).
//! Actors registry
//!
-//! Actor can register itself as a service. Service can be defined as
-//! `ArbiterService` which is unique per arbiter or `SystemService` which is
-//! unique per system.
+//! An Actor can register itself as a service. A Service can be defined as an
+//! `ArbiterService`, which is unique per arbiter, or a `SystemService`, which
+//! is unique per system.
use std::any::{Any, TypeId};
use std::cell::RefCell;
use std::collections::HashMap;
@@ -25,11 +25,11 @@ type AnyMap = HashMap<TypeId, Box<Any>, BuildHasherDefault<FnvHasher>>;
/// Actors registry
///
-/// Actor can register itself as a service. Service can be defined as
-/// `ArbiterService` which is unique per arbiter or `SystemService` which is
-/// unique per system.
+/// An Actor can register itself as a service. A Service can be defined as an
+/// `ArbiterService`, which is unique per arbiter, or a `SystemService`, which
+/// is unique per system.
///
-/// If arbiter service is used outside of running arbiter, it panics.
+/// If an arbiter service is used outside of a running arbiter, it panics.
///
/// # Example
///
@@ -55,7 +55,6 @@ type AnyMap = HashMap<TypeId, Box<Any>, BuildHasherDefault<FnvHasher>>;
/// }
///
/// impl Handler<Ping> for MyActor1 {
-
/// type Result = ();
///
/// fn handle(&mut self, _: Ping, ctx: &mut Context<Self>) {
@@ -70,18 +69,16 @@ type AnyMap = HashMap<TypeId, Box<Any>, BuildHasherDefault<FnvHasher>>;
/// type Context = Context<Self>;
///
/// fn started(&mut self, _: &mut Context<Self>) {
-/// // get MyActor1 addres from the registry
+/// // get MyActor1 address from the registry
/// let act = Arbiter::registry().get::<MyActor1>();
/// act.do_send(Ping);
/// }
/// }
///
-///
/// fn main() {
/// // initialize system
/// let code = System::run(|| {
-///
-/// // Start MyActor1 in new Arbiter
+/// // Start MyActor2 in new Arbiter
/// Arbiter::start(|_| {
/// MyActor2
/// });
@@ -214,9 +211,6 @@ impl Registry {
/// fn main() {
/// // initialize system
/// let code = System::run(|| {
-/// // Start MyActor1
-/// let addr = MyActor1.start();
-///
/// // Start MyActor2
/// let addr = MyActor2.start();
/// });
