Remove needless main() definition from example

src/lib.rs

@@ -35,7 +35,6 @@
 //! You can parse IRC messages using the provided `parse` function.
 //!
 //! ```
-//! fn main() {
 //! let msg = "@id=123;name=rick :nick!user@host.tmi.twitch.tv PRIVMSG #rickastley :Never gonna give you up!";
 //! match ircparser::parse(msg) {
 //!     Ok(x) => {
@@ -54,7 +53,6 @@
 //!         return;
 //!     }
 //! };
-//! }
 //! ```
 
 mod line;