quoted atom parsed as errors in prolog

Hi, reporting here per suggestion on pandoc user list. I was told this is the upstream dep and replicated the error in skylighting (as far as I understand it, first time user, brew install)

```
echo 'afact("Fact").' | skylighting --syntax prolog -f latex

\begin{Shaded}
\begin{Highlighting}[]
\NormalTok{afact(}\OtherTok{"}\ErrorTok{Fact}\OtherTok{"}\NormalTok{)}\KeywordTok{.}
\end{Highlighting}
\end{Shaded}
```

You can see the \ErrorTok command in there. Similar story with html output (span class="er")

```

afact("Fact").

I am told that skylighting relies on data shared or derived from the kate editor. I could not reproduce the problem in Kate on Mac OS, or at least I can say the quote atoms appear in green and not bold red. Not sure which style Kate is using by default. I am a complete Prolog noob, but that looks fine to me and SWI Prolog accepts it. Thanks

Antonio

Start by running the reported `echo 'afact("Fact").' | skylighting --syntax prolog -f latex` command and inspect the Prolog syntax definition or tokenizer derived from KDE syntax highlighting descriptions. Compare the generated LaTeX and HTML classifications with the behavior described for Kate and SWI-Prolog; done means quoted atoms are no longer emitted as errors in both outputs.

Written by the indexing model from the issue text.