Don't point out return span on every E0308

src/test/ui/closures/issue-84128.stderr

@@ -6,11 +6,6 @@ LL |         Foo(())
    |         |
    |         arguments to this struct are incorrect
    |
-note: return type inferred to be `{integer}` here
-  --> $DIR/issue-84128.rs:10:20
-   |
-LL |             return Foo(0);
-   |                    ^^^^^^
 note: tuple struct defined here
   --> $DIR/issue-84128.rs:5:8
    |

src/test/ui/mismatched_types/dont-point-return-on-E0308.rs

@@ -0,0 +1,18 @@
+// edition:2021
+
+async fn f(_: &()) {}
+//~^ NOTE function defined here
+//~| NOTE
+// Second note is the span of the underlined argument, I think...
+
+fn main() {
+    (|| async {
+        Err::<(), ()>(())?;
+        f(());
+        //~^ ERROR mismatched types
+        //~| NOTE arguments to this function are incorrect
+        //~| NOTE expected `&()`, found `()`
+        //~| HELP consider borrowing here
+        Ok::<(), ()>(())
+    })();
+}

src/test/ui/mismatched_types/dont-point-return-on-E0308.stderr

@@ -0,0 +1,19 @@
+error[E0308]: mismatched types
+  --> $DIR/dont-point-return-on-E0308.rs:10:11
+   |
+LL |         f(());
+   |         - ^^
+   |         | |
+   |         | expected `&()`, found `()`
+   |         | help: consider borrowing here: `&()`
+   |         arguments to this function are incorrect
+   |
+note: function defined here
+  --> $DIR/dont-point-return-on-E0308.rs:3:10
+   |
+LL | async fn f(_: &()) {}
+   |          ^ ------
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.