removes comma from features comment
There's a comma when explaining the features mod that breaks the sentence awkwardly.
@@ -99,7 +99,7 @@ pub mod features {
#![cfg_attr(feature = "os-poll", doc = "## `os-poll` (enabled)")]
#![cfg_attr(not(feature = "os-poll"), doc = "## `os-poll` (disabled)")]
//!
- //! Mio by default provides only a shell implementation, that `panic!`s the
+ //! Mio by default provides only a shell implementation that `panic!`s the
//! moment it is actually run. To run it requires OS support, this is
//! enabled by activating the `os-poll` feature.
//!
