rustdoc: remove redundant item kind class from `.item-decl > pre`

This class originated in the very first commit of `rustdoc_ng`, and was used
to add a color border around the item decl based on its kind.

https://github.com/rust-lang/rust/blob/4fd061c426902b0904c65e64a3780b21f9ab3afb/src/rustdoc_ng/html/static/main.css#L102-L106

The item decl no longer has a border, and there aren't any
kind-specific styles in modern rustdoc's rendering of this UI item.

Most of this commit is updating test cases so that they use `item-decl` to
find the `<pre>` tag instead of relying on the fact that the class name
had `rust {kind}` in it while other `<pre>` tags only had class `rust`.

1 files changed, 4 insertions, 4 deletions

diff --git a/tests/rustdoc/array-links.rs b/tests/rustdoc/array-links.rs
index 07f92ac51b9..e7c0ee2de1a 100644
--- a/tests/rustdoc/array-links.rs
+++ b/tests/rustdoc/array-links.rs
@@ -4,25 +4,25 @@
 pub struct MyBox<T: ?Sized>(*const T);
 
 // @has 'foo/fn.alpha.html'
-// @snapshot link_slice_u32 - '//pre[@class="rust fn"]/code'
+// @snapshot link_slice_u32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn alpha() -> &'static [u32; 1] {
     loop {}
 }
 
 // @has 'foo/fn.beta.html'
-// @snapshot link_slice_generic - '//pre[@class="rust fn"]/code'
+// @snapshot link_slice_generic - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn beta<T>() -> &'static [T; 1] {
     loop {}
 }
 
 // @has 'foo/fn.gamma.html'
-// @snapshot link_box_u32 - '//pre[@class="rust fn"]/code'
+// @snapshot link_box_u32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn gamma() -> MyBox<[u32; 1]> {
     loop {}
 }
 
 // @has 'foo/fn.delta.html'
-// @snapshot link_box_generic - '//pre[@class="rust fn"]/code'
+// @snapshot link_box_generic - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn delta<T>() -> MyBox<[T; 1]> {
     loop {}
 }