The Writers Guild of America East has selected Keith Patterson as the recipient of its documentary screenplay award for “Ann Richards’ Texas.”The kudo was announced Saturday at the AFI-Discovery Channel Silverdocs Festival. The docu covers Richards’ rise in the Democratic Party and her turn as governor of Texas. The award carries a prize of $1,000 and a five-year membership in the WGA East Nonfiction Writers Caucus. The other nominees were “Plimpton! Starring George Plimpton as Himself,” written, directed and produced by Thomas Bean and Luke Poling; “Photgraphic Memory,” written by Ross McElwee in collaboration with Marie Emmanuelle Hartness, directed by Ross McElwee; “Portrait of Wally,” written, directed and produced by Andrew Shea, written and produced by David D’Arcy; “Chasing Ice,” written by Mark Monroe; “Beauty Is Embarrassing,” written by Neil Berkeley, Chris Bradley, and Kevin Klauber, directed by Berkeley, produced by Berkeley and Bradley.