Rollup merge of rust-lang#80864 - ericseppanen:master, r=jyn514

std/core docs: fix wrong link in PartialEq

PartialEq doc was attempting to link to ``[`Eq`]`` but instead we got a link to `` `eq` ``. Disambiguate with `trait@Eq`.

You can see the bad link [here](https://doc.rust-lang.org/std/cmp/trait.PartialEq.html) (Second sentence, "floating point types implement PartialEq but not Eq").

Author: JohnTitor

library/core/src/cmp.rs

@@ -29,7 +29,7 @@ use self::Ordering::*;
 ///
 /// This trait allows for partial equality, for types that do not have a full
 /// equivalence relation. For example, in floating point numbers `NaN != NaN`,
-/// so floating point types implement `PartialEq` but not [`Eq`].
+/// so floating point types implement `PartialEq` but not [`trait@Eq`].
 ///
 /// Formally, the equality must be (for all `a`, `b` and `c`):
 ///