Stand-up comedian Steve Trevino claims his nickname is “Sexy Mexy” (sure it is, Steve). He’s a frequent cohort of Carlos Mencia, but don’t let that discourage you from seeing him at the Improv today. Yes, the “I’m-Latino-and-want-to-yell-about-it” shtick became risqué, cool and then boring really quickly, but the Portland, Texas-born…