chore: Fix typos (#201)

src/lib.rs

@@ -1639,7 +1639,7 @@ impl Async<UdpSocket> {
 
     /// Sends data to the specified address.
     ///
-    /// Returns the number of bytes writen.
+    /// Returns the number of bytes written.
     ///
     /// # Examples
     ///

src/os/unix.rs

@@ -15,7 +15,7 @@ use std::os::unix::io::BorrowedFd;
 /// associated with `poll()`, this function will return `None`.
 ///
 /// There is presently no way to stop the "`async-io`" thread from being launched, so the reactor
-/// will still be continiously polled on that thread. This fact should be kept in mind by anyone
+/// will still be continuously polled on that thread. This fact should be kept in mind by anyone
 /// looking to integrate `async-io` into another runtime using this function.
 ///
 /// It is possible to use this function to call raw system calls on the underlying event source.

src/os/windows.rs

@@ -28,7 +28,7 @@ use std::task::{Context, Poll};
 /// ## Implementation
 ///
 /// The current implementation waits on the handle by registering it in the application-global
-/// Win32 threadpool. However, in the futur it may be possible to migrate to an implementation
+/// Win32 threadpool. However, in the future it may be possible to migrate to an implementation
 /// on Windows 10 that uses a mechanism similar to [`MsgWaitForMultipleObjectsEx`].
 ///
 /// [`MsgWaitForMultipleObjectsEx`]: https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-msgwaitformultipleobjectsex