'(LEFT-offset . RIGHT-offset). This offset is added to the
attachments to prevent ugly slurs. [fixme: we need more documentation here].
")
-(grob-property-description 'auto-interstaff-knee-gap number? "")
-(grob-property-description 'auto-knee-gap number? "")
+(grob-property-description 'auto-knee-gap number? "The vertical distance of two adjacent beamed notes beyond which to make a knee.")
(grob-property-description 'axes list? "list of axis numbers.