German chords with uppercase bass

[Henning Hraban Ramm]

As is shown e.g. in 
https://lilypond.org/doc/v2.22/Documentation/snippets-big-page.de.html 
“Changing the chord names to German or semi-German notation”, 
\germanChords changes bass notes of chords like a:m/c to lowercase.

While I don’t believe that this is common in Germany, I really would 
like to get German chords (i.e. H instead of B) with uppercase bass 
notes – as I know it from all my (German) songbooks.

I’m sure there’s a clever setting or Scheme snippet for that.
Can you help me?

Hraban

% MWE from the quoted snippet:

scm = \chordmode {
  c1/c | cis/cis
  b1/b | bis/bis | bes/bes
}

<<
  \new ChordNames {
    \germanChords \scm
  }
  \context Voice { \scm }
>>