Problem with LaTeX code for multi-line comments with blank lines

[jespercockx]

In #2588 , @bafain reports the following:

There seems to be a problem with the LaTeX code generated for multi-line comments that contain blank lines.

Agda version: 2.6.2-292237b
XeTeX version: 3.14159265-2.6-0.999991 (TeX Live 2019/Arch Linux)
Literate Agda file Test.lagda:

\documentclass{article}
\usepackage{agda}
\begin{document}
\begin{code}
module Test where

{-
-}

{-
A
-}

{-
B
B
-}

{-
C

C
-}
\end{code}
\end{document}

Generated LaTeX file latex/Test.tex:

[..]
\>[0]\AgdaComment{\{-
C

C
-\}}\<%
[..]

Error:

$ agda --latex Test.lagda
$ cd latex
$ xelatex Test.tex 
[..]
Runaway argument?
{\textcolor {AgdaComment}{\{- C 
! Paragraph ended before \text@command was complete.
<to be read again> 
                   \par 
l.34 \end{code}

? 

[andreasabel]

A fix seems to be:

• wrap each non-empty comment line into its own \AgdaComment macro,
• output empty comment lines as such.

This is basically #2588 (comment) (@nad):

A simple fix might be to extend stringLiteral to handle comments as well.