StemTremolo collides with natural Accidental

[Malte Meyn]

> I'm not top posting.

Hello list,

for StemTremolos in short durations the length of a Stem is increased. But
it is not long enough when a natural Accidental is directly placed in front
of the note, so they collide:

\version "2.19.22"

{
  b'!2:16 % default stem length, doesn’t collide
  b'!2:32 % stem length increased but not enough
}

Flats don’t collide and the collision with sharps is very small but exists.

Malte