CLEVELAND, Ohio — Cleveland native Tracy Chapman stole the show at Sunday night’s Grammy Awards, making a surprise appearance to sing her 1988 hit, “Fast Car,” in a duet with Luke Combs. whose cover of the song became a No. 1 country hit last year. The tender, elegant performance was a highlight of the evening and a hit among the many celebrities in attendance, including Taylor Swift, who could be seen standing in the crowd singing along to every word.