Add NAG support to export mode

[orenlivne]

If a game contains NAGs, \mainline prints them. But if the game is exported and then printed with \printchessgame, the NAG disappear. Underlying issue: the export file misses a \makeatletter/\makeatother and \printchessgames doesn't use it. See also: https://tex.stackexchange.com/questions/631137/how-to-print-nags-in-xskak-printchessgame

Example: `\documentclass{book} \usepackage{xskak}

\begin{document} \newchessgame[white=none,black=none,id=export] \mainline{1. d4 Nf6 $1} \ \xskakexportgames[file=test, games={export}] \input{test.xsk} \printchessgame \end{document}`

Temporary workaround (won't be needed after bug fix): ` \documentclass{book} \usepackage{xskak}

\begin{document} \newchessgame[white=none,black=none,id=export] \mainline{1. d4 Nf6 $1 2. Nf3 c5?} \xskakexportgames[file=test, games={export,export}]

\makeatletter \input{test.xsk} \gdef\xskak@do@printmove{\xskakget{san}\xskakget{comments}\xskakget{nag}} \makeatother
\printchessgame \end{document}`

[tommarcoen]

I have the same issue though I already found a temporary workaround on Stack Exchange.

[tommarcoen]

About half the time it does not work and the NAG does not get printed in the PDF even though it is available in the xsk file. I will try and create a MWE soon.