syntax highlighting broken

### Reproduction

```hs
liftIO $ printf "\
\Shot at: %d %d\n\
\Result: %s\n\
\" {- syntax highlighting broken \"" -} x y $ show res
```

Start by reproducing the Haskell snippet in the issue, especially the escaped strings and inline comment, and trace the playground's syntax-highlighting entry point. No source file or test is named in the report, so locate the highlighting implementation and its existing tests first. Done means the reproduced snippet is highlighted correctly without breaking other Haskell examples.

Written by the indexing model from the issue text.