Top executives at CBS News have banned staffers from using the word “transgender” when reporting on Nashville shooter — despite the fact police have said Audrey Hale was transgender and cited it as a key point in the case, The Post has learned. “The shooter’s gender identity has not been confirmed by CBS News,” the network’s executives insisted in a Tuesday memo obtained by The Post. “As such, we should avoid any mention of it as it has no known relevance to the crime. Should that change, we can and will revisit.”