putting bracket above fingering instruction

[Rob van den Berg]

I mainly use lilypond for writing/arranging educational music for my
keyboard and piano students.
In the books we use it is common practice to put a small brack (┌┐)
above a fingering instruction when the hand has to change position on
the keyboard.
How can I achieve this with lilypond and if it can't be done could
this become a sponsered feature :-)

Regards,
Rob