How to add thumb fingerings

Special scripts can be entered for thumb fingerings (for example in cello music).

\version "2.24"

%% http://lsr.di.unimi.it/LSR/Item?id=415

%LSR modified by P.P.Schneider on Feb.2014 for v2.18

\relative c'' {
  a2_\thumb
  \override Fingering.add-stem-support = ##t
  <b_\thumb b'-3>
}