“The High Note” began life as a screenplay titled “Covers,” and at times the music-themed drama turns into a tribute to the power of a cover song performed by someone other than the person who originated it: Aretha Franklin with Bobby “Blue” Bland’s “Share Your Love,” the Staples Singers with the Band’s “The Weight,” P.P Arnold with Cat Stevens’ “The First Cut Is the Deepest,” the Dixie Chicks with Fleetwood Mac’s “Landslide” …