Fix kdb_write doctest by wrapping example in function

Author: 0-jake-0

wingfoil/src/adapters/kdb/write.rs

@@ -43,6 +43,7 @@ pub trait KdbSerialize: Sized {
 /// ```ignore
 /// use wingfoil::adapters::kdb::*;
 /// use wingfoil::*;
+/// use std::time::Duration;
 ///
 /// #[derive(Debug, Clone, Default)]
 /// struct Trade {
@@ -61,11 +62,14 @@ pub trait KdbSerialize: Sized {
 ///     }
 /// }
 ///
-/// let conn = KdbConnection::new("localhost", 5000);
-/// let trades: Rc<dyn Stream<TinyVec<[Trade; 1]>>> = /* ... */;
-/// kdb_write(conn, "trades", &trades)
-///     .run(RunMode::RealTime, RunFor::Duration(Duration::from_secs(10)))
-///     .unwrap();
+/// fn example() {
+///     let conn = KdbConnection::new("localhost", 5000);
+///     let trades: Rc<dyn Stream<TinyVec<[Trade; 1]>>> = /* ... */
+/// #       panic!("example code");
+///     kdb_write(conn, "trades", &trades)
+///         .run(RunMode::RealTime, RunFor::Duration(Duration::from_secs(10)))
+///         .unwrap();
+/// }
 /// ```
 pub fn kdb_write<T>(
     connection: KdbConnection,