Convert Listing 9-12 to <Listing>

(had to fix a conflect here)

src/ch09-02-recoverable-errors-with-result.md

@@ -492,12 +492,13 @@ code will now compile.
 
 <span class="filename">Filename: src/main.rs</span>
 
+<Listing number="9-12" caption="Changing `main` to return `Result<(), E>` allows the use of the `?` operator on `Result` values.">
+
 ```rust,ignore
 {{#rustdoc_include ../listings/ch09-error-handling/listing-09-12/src/main.rs}}
 ```
 
-<span class="caption">Listing 9-12: Changing `main` to return `Result<(), E>`
-allows the use of the `?` operator on `Result` values.</span>
+</Listing>
 
 The `Box<dyn Error>` type is a *trait object*, which we’ll talk about in the
 [“Using Trait Objects that Allow for Values of Different