Add speaker note about reference equality (#2670)

src/std-traits/comparisons.md

@@ -54,21 +54,35 @@ impl PartialOrd for Citation {
 
 <details>
 
-`PartialEq` can be implemented between different types, but `Eq` cannot, because
+- `PartialEq` can be implemented between different types, but `Eq` cannot,
-it is reflexive:
+  because it is reflexive:
 
-```rust,editable
+  ```rust,editable
-struct Key {
+  struct Key {
       id: u32,
       metadata: Option<String>,
-}
+  }
-impl PartialEq<u32> for Key {
+  impl PartialEq<u32> for Key {
       fn eq(&self, other: &u32) -> bool {
           self.id == *other
       }
-}
+  }
-```
+  ```
 
-In practice, it's common to derive these traits, but uncommon to implement them.
+- In practice, it's common to derive these traits, but uncommon to implement
+  them.
+
+- When comparing references in Rust, it will will compare the value of the
+  things pointed to, it will NOT compare the references themselves. That means
+  that references to two different things can compare as equal if the values
+  pointed to are the same:
+
+  ```rust,editable
+  fn main() {
+      let a = "Hello";
+      let b = String::from("Hello");
+      assert_eq!(a, b);
+  }
+  ```
 
 </details>