The Cubs rookie posted the first immaculate inning for the team in 18 years. The “immaculate inning” — where a pitcher strikes out all three batters he faces on nine pitches — has become more common in recent years as strikeouts in general have increased. They’re still fairly rare, and until Thursday night, no Cubs pitcher had thrown one in 18 years, since LaTroy Hawkins did it against the Marlins September 11, 2004. Thursday, Hayden Wesneski did it in just his second MLB start (fourth appearance). It was yet another excellent outing from Wesneski, and the Cubs hung on for…