rustdoc: rename /implementors to /impl.trait

This is shorter, avoids potential conflicts with a crate
named `implementors`[^1], and will be less confusing when JS
include files are added for type aliases.

[^1]: AFAIK, this couldn't actually cause any problems right now,
but it's simpler just to make it impossible than relying on never
having a file named `trait.Foo.js` in the crate data area.

src/librustdoc/html/render/print_item.rs

@@ -1101,7 +1101,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
     // ```
     //
     // Basically, we want `C::Baz` and `A::Foo` to show the same set of
-    // impls, which is easier if they both treat `/implementors/A/trait.Foo.js`
+    // impls, which is easier if they both treat `/trait.impl/A/trait.Foo.js`
     // as the Single Source of Truth.
     //
     // We also want the `impl Baz for Quux` to be written to
@@ -1110,7 +1110,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
     // because that'll load faster, and it's better for SEO. And we don't want
     // the same impl to show up twice on the same page.
     //
-    // To make this work, the implementors JS file has a structure kinda
+    // To make this work, the trait.impl/A/trait.Foo.js JS file has a structure kinda
     // like this:
     //
     // ```js
@@ -1127,7 +1127,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
     // So C's HTML will have something like this:
     //
     // ```html
-    // <script src="/implementors/A/trait.Foo.js"
+    // <script src="/trait.impl/A/trait.Foo.js"
     //     data-ignore-extern-crates="A,B" async></script>
     // ```
     //
@@ -1137,7 +1137,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
     // [JSONP]: https://en.wikipedia.org/wiki/JSONP
     let mut js_src_path: UrlPartsBuilder = std::iter::repeat("..")
         .take(cx.current.len())
-        .chain(std::iter::once("implementors"))
+        .chain(std::iter::once("trait.impl"))
         .collect();
     if let Some(did) = it.item_id.as_def_id() &&
         let get_extern = { || cache.external_paths.get(&did).map(|s| &s.0) } &&

src/librustdoc/html/render/write_shared.rs

@@ -362,7 +362,7 @@ if (typeof exports !== 'undefined') {exports.searchIndex = searchIndex};
     }
 
     // Update the list of all implementors for traits
-    let dst = cx.dst.join("implementors");
+    let dst = cx.dst.join("trait.impl");
     let cache = cx.cache();
     for (&did, imps) in &cache.implementors {
         // Private modules can leak through to this phase of rustdoc, which

tests/rustdoc-gui/code-tags.goml

@@ -1,6 +1,6 @@
 // This test ensures that items and documentation code blocks are wrapped in <pre><code>
 
-// We need to disable this check because `implementors/test_docs/trait.AnotherOne.js`
+// We need to disable this check because `trait.impl/test_docs/trait.AnotherOne.js`
 // doesn't exist.
 fail-on-request-error: false
 go-to: "file://" + |DOC_PATH| + "/test_docs/fn.foo.html"

tests/rustdoc-gui/item-decl-colors.goml

@@ -1,6 +1,6 @@
 // This test ensures that the color of the items in the type decl are working as expected.
 
-// We need to disable this check because `implementors/test_docs/trait.TraitWithoutGenerics.js`
+// We need to disable this check because `trait.impl/test_docs/trait.TraitWithoutGenerics.js`
 // doesn't exist.
 fail-on-request-error: false
 

tests/rustdoc-gui/no-docblock.goml

@@ -1,6 +1,6 @@
 // This test checks that there are margins applied to methods with no docblocks.
 
-// We need to disable this check because `implementors/test_docs/trait.TraitWithNoDocblock.js`
+// We need to disable this check because `trait.impl/test_docs/trait.TraitWithNoDocblock.js`
 // doesn't exist.
 fail-on-request-error: false
 

tests/rustdoc-gui/setting-auto-hide-content-large-items.goml

@@ -1,7 +1,7 @@
 // This test ensures that the "Auto-hide item contents for large items" setting is working as
 // expected.
 
-// We need to disable this check because `implementors/test_docs/trait.Iterator.js` doesn't exist.
+// We need to disable this check because `trait.impl/test_docs/trait.Iterator.js` doesn't exist.
 fail-on-request-error: false
 
 define-function: (

tests/rustdoc-gui/trait-sidebar-item-order.goml

@@ -1,6 +1,6 @@
 // Checks that the elements in the sidebar are alphabetically sorted.
 
-// We need to disable this check because `implementors/test_docs/trait.AnotherOne.js`
+// We need to disable this check because `trait.impl/test_docs/trait.AnotherOne.js`
 // doesn't exist.
 fail-on-request-error: false
 

tests/rustdoc-gui/type-declation-overflow.goml

@@ -2,7 +2,7 @@
 // This test ensures that the items declaration content overflow is handled inside the <pre> directly.
 
 // We need to disable this check because
-// `implementors/test_docs/trait.ALongNameBecauseItHelpsTestingTheCurrentProblem.js`
+// `trait.impl/test_docs/trait.ALongNameBecauseItHelpsTestingTheCurrentProblem.js`
 // doesn't exist.
 fail-on-request-error: false
 

tests/rustdoc/hidden-impls.rs

@@ -12,6 +12,6 @@ pub mod __hidden {
 
 // @has foo/trait.Clone.html
 // @!hasraw - 'Foo'
-// @has implementors/core/clone/trait.Clone.js
+// @has trait.impl/core/clone/trait.Clone.js
 // @!hasraw - 'Foo'
 pub use std::clone::Clone;

tests/rustdoc/impl-parts-crosscrate.rs

@@ -12,7 +12,7 @@ pub struct Bar<T> { t: T }
 // full impl string.  Instead, just make sure something from each part
 // is mentioned.
 
-// @hasraw implementors/rustdoc_impl_parts_crosscrate/trait.AnAutoTrait.js Bar
+// @hasraw trait.impl/rustdoc_impl_parts_crosscrate/trait.AnAutoTrait.js Bar
 // @hasraw - Send
 // @hasraw - !AnAutoTrait
 // @hasraw - Copy

tests/rustdoc/inline_cross/implementors-js.rs

@@ -4,13 +4,13 @@
 
 extern crate implementors_inline;
 
-// @!has implementors/implementors_js/trait.MyTrait.js
-// @has implementors/implementors_inline/my_trait/trait.MyTrait.js
-// @!has implementors/implementors_inline/prelude/trait.MyTrait.js
+// @!has trait.impl/implementors_js/trait.MyTrait.js
+// @has trait.impl/implementors_inline/my_trait/trait.MyTrait.js
+// @!has trait.impl/implementors_inline/prelude/trait.MyTrait.js
 // @has implementors_inline/my_trait/trait.MyTrait.html
-// @has - '//script/@src' '../../implementors/implementors_inline/my_trait/trait.MyTrait.js'
+// @has - '//script/@src' '../../trait.impl/implementors_inline/my_trait/trait.MyTrait.js'
 // @has implementors_js/trait.MyTrait.html
-// @has - '//script/@src' '../implementors/implementors_inline/my_trait/trait.MyTrait.js'
+// @has - '//script/@src' '../trait.impl/implementors_inline/my_trait/trait.MyTrait.js'
 /// When re-exporting this trait, the HTML will be inlined,
 /// but, vitally, the JavaScript will be located only at the
 /// one canonical path.

tests/rustdoc/issue-43701.rs

@@ -2,4 +2,4 @@
 
 pub use std::vec::Vec;
 
-// @!has implementors/core/clone/trait.Clone.js
+// @!has trait.impl/core/clone/trait.Clone.js