Rollup merge of #38671 - ollie27:rustdoc_stab_em_div_fix, r=frewsxcv

rustdoc: Fix broken CSS for trait items

The `stab` class shouldn't have any effect here so can be removed as currently it adds an outline.

This was accidentally caused by #38329.

[before](https://doc.rust-lang.org/nightly/std/iter/trait.ExactSizeIterator.html) [after](https://ollie27.github.io/rust_doc_test/std/iter/trait.ExactSizeIterator.html)

src/librustdoc/html/render.rs

@@ -2057,10 +2057,9 @@ fn item_trait(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
         let item_type = m.type_();
         let id = derive_id(format!("{}.{}", item_type, name));
         let ns_id = derive_id(format!("{}.{}", name, item_type.name_space()));
-        write!(w, "<h3 id='{id}' class='method stab {stab}'>\
+        write!(w, "<h3 id='{id}' class='method'>\
                    <span id='{ns_id}' class='invisible'><code>",
                id = id,
-               stab = m.stability_class(),
                ns_id = ns_id)?;
         render_assoc_item(w, m, AssocItemLink::Anchor(Some(&id)), ItemType::Impl)?;
         write!(w, "</code>")?;