I want my score to show C#m7(b5) instead of C#ø.

As per https://music.stackexchange.com/questions/122356/lilypond-half-diminished-seventh-symbol, I've created the following exception:

```
chExceptions = {
  <c ees ges b>1-\markup {"m7(" \char ##x266D "5)" }
}
```

and in the score section 

```
\chords {
  \set noChordSymbol = ""
  \set chordNameExceptions = #chExceptions
  r2 e2 a2:m6/c b2:7 e4:m b4:7 e4:m cis4:m7.5-
}
```

but the last chord is rendered as 

[![C-sharp half diminished chord symbol][1]][1]

How do I make it render like this:

[![C-sharp minor 7, flat 5 chord symbol][2]][2]


  [1]: https://i.sstatic.net/bLlIh.png
  [2]: https://i.sstatic.net/NOIU3.png