message: docs(ffi): spelling error
diff: @@ -7,10 +7,10 @@ use tokio::io::{AsyncRead, AsyncWrite};
  use super::task::hyper_context;
  -/// Sentinal value to return from a read or write callback that the operation
  +/// Sentinel value to return from a read or write callback that the operation
  /// is pending.
  pub const HYPER_IO_PENDING: size_t = 0xFFFFFFFF;
  -/// Sentinal value to return from a read or write callback that the operation
  +/// Sentinel value to return from a read or write callback that the operation
  /// has errored.
  pub const HYPER_IO_ERROR: size_t = 0xFFFFFFFE;
  