(Doc) Enable rt-multi-thread feature for sample code (#10770)

docs/source/user-guide/example-usage.md

@@ -30,7 +30,7 @@ crates.io] page. Add the dependency to your `Cargo.toml` file:
 
 ```toml
 datafusion = "latest_version"
-tokio = "1.0"
+tokio = { version = "1.0", features = ["rt-multi-thread"] }
 ```
 
 ## Add latest non published DataFusion dependency