Add documentation for SyncIoBridge with examples and alternatives

tokio-util/src/io/sync_bridge.rs

@@ -47,7 +47,7 @@ use tokio::io::{
 /// tokio::io::copy(&mut reader, &mut encoder).await?;
 /// ```
 ///
-/// ## Example 3: Parsing JSON
+/// ## Example 3: Parsing `JSON`
 ///
 /// When parsing `JSON` data, avoid using `SyncIoBridge` with `serde_json::from_reader` as it may cause blocking operations.
 /// Instead, read the data into a `Vec<u8>` and parse it using `serde_json::from_slice`.