markups and accents inside staff

[Jim Cline]

Apologies in advance; this seems like it must be simple, but I cannot find 
the answer.  I would like to be able to move an accent closer to the note 
head, possibly using markup since it would also be nice to know how to get 
markups to print over the staff lines.  Here is an example:

%%%
\version "2.20.0"
\relative c {
  \time 3/4
  \mergeDifferentlyDottedOn
  <<{<g'' c f>4\arpeggio e' d}\\{ g,8._> dis16 a2}>>|
}

The accent prints below the beam, and I would like it higher, closer to 
the note head, even if there is some collision with the stem or the staff.
But \vspace in markup does not allow me to do it.  --Jim