ah yes,
i did look, but i skipped over the preamble to 'line-interface'
what you might see if you're /skimming/ this doc page in search of
style is the list of user settable properties where you find, just as
in PianoPedalBracket:
style (symbol)
This setting determines in what style a grob is typeset. Valid
choices depend on the stencil callback reading this property.
and so you'll go on searching
i would have found it if the entry was
*#'style* = #'symbol
This setting determines in what style a grob is typeset.
The property *style* can be line, dashed-line, trill, dotted-line
or zigzag.
Valid choices depend on the stencil callback reading this property.