Update idioms/priv-extend.md

rust-unofficial · simonsan · Sep 1, 2021 · Jan 2, 2021 · Jan 3, 2021 · Jan 3, 2021
commit a68505863f2b6fbe807412b9d28be319efd81920
diff --git a/idioms/priv-extend.md b/idioms/priv-extend.md
@@ -25,7 +25,7 @@ code paths that are only executed in extremely rare circumstances.
 
 ## Example
 
-```rust,ignore
+```rust
 mod a {
     // Public struct.
     #[non_exhaustive]