Suggested [bracketed] acciaccatura: HowTo

[Valerio M. Pelliccioni]

Hi,
I need a way to put a stroke on a grace in way that I can engrave an 
acciaccatura w/o the expected slur.
This grace note should also be put in bracket.
In the attached example there is the best that I can.
version "2.10.23"
squareAcciaccatura = ^markup {
tiny
override Stem #'stroke-style = #"grace"
bracket note #"8" #+0.75
}

Thanks for any help!
Valerio