Catherine O’Hara will make a posthumous appearance in Martin Short’s forthcoming Netflix documentary , “Marty, Life is Short.” The late “Schitt’s Creek” star — who first met Short in the early ’70s while coming up in Toronto’s improv scene — made a brief cameo in the documentary’s trailer , which was released on Friday. “I feel like he could improvise to eternity. Couldn’t he?” O’Hara — who conducted her interview before her death earlier this year — says in the teaser. Catherine O’Hara will make a posthumous appearance in Martin Short’s forthcoming Netflix documentary, “Marty, Life is Short,” as pictured above. Courtesy of Netflix O’Hara’s appearance was revealed after she made a brief cameo in the film’s trailer (pictured above), which was released Friday. Courtesy of Netflix A second clip included in the trailer showed Short playfully filming O’Hara, telling her “I loved you in ‘Home Alone!’ You were wonderful!” while she laughs at his compliment.…