CNBC's Jim Cramer on Friday prepared investors for next week on Wall Street, saying investors should pay attention as earnings season continues, with reports from companies including Shopify, Marriott and Wendy's.He also recommended researching retail stocks next week before the industry reports a slew of earnings results the week after."Next week seems busy, but, you know what, it's a classic interregnum — Google that — before we get to retail earnings," Cramer said. "Remember, those heavy earnings weeks a ...