Rollup merge of #78793 - camelid:fixup-structuraleq, r=jyn514

Clean up `StructuralEq` docs

library/core/src/marker.rs

@@ -156,18 +156,18 @@ pub trait StructuralPartialEq {
 /// Required trait for constants used in pattern matches.
 ///
 /// Any type that derives `Eq` automatically implements this trait, *regardless*
-/// of whether its type-parameters implement `Eq`.
+/// of whether its type parameters implement `Eq`.
 ///
-/// This is a hack to workaround a limitation in our type-system.
+/// This is a hack to work around a limitation in our type system.
 ///
-/// Background:
+/// # Background
 ///
 /// We want to require that types of consts used in pattern matches
 /// have the attribute `#[derive(PartialEq, Eq)]`.
 ///
 /// In a more ideal world, we could check that requirement by just checking that
-/// the given type implements both (1.) the `StructuralPartialEq` trait *and*
+/// the given type implements both the `StructuralPartialEq` trait *and*
-/// (2.) the `Eq` trait. However, you can have ADTs that *do* `derive(PartialEq, Eq)`,
+/// the `Eq` trait. However, you can have ADTs that *do* `derive(PartialEq, Eq)`,
 /// and be a case that we want the compiler to accept, and yet the constant's
 /// type fails to implement `Eq`.
 ///
@@ -176,8 +176,11 @@ pub trait StructuralPartialEq {
 /// ```rust
 /// #[derive(PartialEq, Eq)]
 /// struct Wrap<X>(X);
+///
 /// fn higher_order(_: &()) { }
+///
 /// const CFN: Wrap<fn(&())> = Wrap(higher_order);
+///
 /// fn main() {
 ///     match CFN {
 ///         CFN => {}