Kenan Thompson was “hit hard” by the death of his former “All That” co-star Christy Knowings, who died Tuesday at 46 following an asthma attack. Thompson, who appeared on the Nickelodeon sketch show with Knowings from 1997 to 1999, paid an emotional tribute hours after news of her death broke Thursday. “Man this one hit hard!!! Rest well Christy!!! Never could have imagined this day!! Sending so much love to her family!! She was a real one and one of the funniest people out here!!! Gonna miss you buddy!!!” the “Saturday Night Live” star wrote on Instagram. Thompson’s “Kenan & Kel” co-star Kel Mitchell, 47, also remembered their former…
