Haskell backend prints a list `[Char]` containing characters as string

Grammar
```ebnf
(:[]). [Char] ::= "*" Char ";";
(:).   [Char] ::= "*" Char ";" [Char];
```
and input
```
* 'A';
* 'B';
* 'C';
```
results in printed output
```
"ABC"
```
The other backends print this correctly.
