multi-line markup inside a single box

[Josiah Boothby]

Maybe I'm missing something obvious (it's 1:30 in the morning...it's not
unlikely!), but I'm trying to include a small two-line markup inside a
single box. The thing that seems obvious is producing two boxed lines,
which is not what I'm aiming for and is too visually cluttered for me to
accept as a compromise:

\markup\right-column\box{
  \line{Solos: 1st x tpt}
  \line{2nd x clr}
}

Any ideas?

Thanks!

—Josiah