If the Boston Music Awards’ Best New Artist field is a snapshot of the new generation of greater Boston musicians, it’s a hopeful one. The area’s flourishing hip-hop and DIY scenes are well represented, and a crop of bedroom pop artists are putting their own stamp on Top 40 sounds. It is appropriate to describe the field as “diverse,” in more than one sense; mixed-gender rock bands are the norm, and Black artists distinguish themselves in genres where the BMAs have typically favored white musicians. Perhaps the end of White Guy Indie Rock is finally at hand.