As the poet Eve Plumb once said … marsh girl, marsh girl, marsh girl! Everyone in the trailer for Where the Crawdads Sing is always talking about this “marsh girl,” a 5 percent feral young woman played by Daisy Edgar-Jones. She is the town bogeywoman, but deep down you know she’s a good person because she is played by someone pretty, and that’s how these things tend to go. This trailer’s got it all: a courtroom scene with your bog-standard (pun intended) southern lawyer, a heron in flight, and boys that look as if they wandered on set from the Nicholas Sparks film shooting one lot over. The movie is based on the best-selling book by Delia Owens, who might have been inspired by her own family’s implication in a Zambian murder. Yikes! Statistically, if you’re in a book club or you’re producer Reese Witherspoon, you’ve read this book already,…