Auto merge of #22133 - servo:extern-crate, r=SimonSapin

Use 2018-edition idioms in crates that use that edition

The first commit is almost entirely mechanical, created by running `cargo fix --edition-idioms` and relevant crates. I undid the change of adding an anonymous lifetime parameter in types that have implicit lifetimes parameters, for example replacing `&mut Formatter` with `&mut Formatter<'_>`, because I don’t like it. The remaining changes are, in many places:

* Add `dyn` to trait object types, for example `Rc<gl::Gl>` to `Rc<dyn gl::Gl>`. This change also works in the 2015 edition.
* Remove `extern crate` where is it made unneeded by changes to the import/module system.

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1 files changed, 0 insertions, 10 deletions

diff --git a/components/devtools/lib.rs b/components/devtools/lib.rs
index be40e70eec6..0768a79ed09 100644
--- a/components/devtools/lib.rs
+++ b/components/devtools/lib.rs
@@ -12,20 +12,10 @@
 #![allow(non_snake_case)]
 #![deny(unsafe_code)]
 
-extern crate devtools_traits;
-extern crate headers_core;
-extern crate headers_ext;
-extern crate http;
-extern crate hyper;
-extern crate ipc_channel;
 #[macro_use]
 extern crate log;
-extern crate msg;
 #[macro_use]
 extern crate serde;
-extern crate serde_json;
-extern crate servo_channel;
-extern crate time;
 
 use crate::actor::{Actor, ActorRegistry};
 use crate::actors::browsing_context::BrowsingContextActor;