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, 6 insertions, 3 deletions

diff --git a/components/script/dom/htmlcollection.rs b/components/script/dom/htmlcollection.rs
index 99d3c4775b8..cc2256a6764 100644
--- a/components/script/dom/htmlcollection.rs
+++ b/components/script/dom/htmlcollection.rs
@@ -69,7 +69,10 @@ pub struct HTMLCollection {
 
 impl HTMLCollection {
     #[allow(unrooted_must_root)]
-    pub fn new_inherited(root: &Node, filter: Box<CollectionFilter + 'static>) -> HTMLCollection {
+    pub fn new_inherited(
+        root: &Node,
+        filter: Box<dyn CollectionFilter + 'static>,
+    ) -> HTMLCollection {
         HTMLCollection {
             reflector_: Reflector::new(),
             root: Dom::from_ref(root),
@@ -99,7 +102,7 @@ impl HTMLCollection {
     pub fn new(
         window: &Window,
         root: &Node,
-        filter: Box<CollectionFilter + 'static>,
+        filter: Box<dyn CollectionFilter + 'static>,
     ) -> DomRoot<HTMLCollection> {
         reflect_dom_object(
             Box::new(HTMLCollection::new_inherited(root, filter)),
@@ -111,7 +114,7 @@ impl HTMLCollection {
     pub fn create(
         window: &Window,
         root: &Node,
-        filter: Box<CollectionFilter + 'static>,
+        filter: Box<dyn CollectionFilter + 'static>,
     ) -> DomRoot<HTMLCollection> {
         HTMLCollection::new(window, root, filter)
     }