staff-line thickness. The shape of the background is determined by
@code{whiteout-style}. Usually @code{#f} by default.")
(whiteout-style ,symbol? "Determines the shape of the
-@code{whiteout} background. Available are @code{'outline} and the
-default @code{'box}.")
+@code{whiteout} background. Available are @code{'outline},
+@code{'rounded-box}, and the default @code{'box}.")
(width ,ly:dimension? "The width of a grob measured in staff
space.")
(word-space ,ly:dimension? "Space to insert between words in