Apply suggestions from code review

Co-authored-by: David Tolnay <[email protected]>

Author: nzrq

std/src/collections/hash/set.rs

@@ -590,8 +590,9 @@ where
     ///
     /// When an equal element is present in `self` and `other`
     /// then the resulting `Intersection` may yield references to
-    /// one or the other, which will be visible in properties of `T`
-    /// not participating in the `Eq` implementation.
+    /// one or the other. This can be relevant if `T` contains fields which
+    /// are not compared by its `Eq` implementation, and may hold different
+    /// value between the two equal copies of `T` in the two sets.
     ///
     /// # Examples
     ///