The 60th annual Grammy Awards on Sunday gave its highest accolades to Bruno Mars, an upbeat master of danceable pop, even as the show wrestled with a range of social and political topics including immigration, race and the #MeToo movement. Mr. Mars won all six of the awards he was nominated for, including the top prizes of album, record and song of the year. The next most rewarded artist was Kendrick Lamar, the provocative and critically admired rapper from Compton, Calif., whose five wins included a sweep of the rap categories. Their victories came at the expense of Jay-Z, now a reigning elder of hip-hop and the music business in general, who had arrived as the most-nominated artist of the night, with eight nods, but went home empty-handed.