test: Fix documendation test

src/blocking.rs

@@ -157,6 +157,7 @@ macro_rules! blocking {
 /// ```no_run
 /// use smol::blocking;
 /// use std::fs;
+/// use futures::stream::StreamExt;
 ///
 /// # smol::run(async {
 /// let mut dir = smol::iter(blocking!(fs::read_dir("."))?);

src/timer.rs

@@ -89,12 +89,12 @@ impl Timer {
     ///
     /// ```
     /// use smol::Timer;
-    /// use std::time::{duration, Instant};
+    /// use std::time::{Duration, Instant};
     ///
     /// # smol::run(async {
     /// let now = Instant::now();
     /// let when = now + Duration::from_secs(1);
-    /// Timer::after(when).await;
+    /// Timer::at(when).await;
     /// # });
     /// ```
     pub fn at(when: Instant) -> Timer {