[tex4ht] adding support for \relax to make4ht mathjax style?

[Nasser M. Abbasi]

I am trying to use make4ht with mathjax. As I find problems, will report them.

I found small problem.

Auto generated latex code sometimes uses \relax, and this seems
not to be supported by the mathjax make4ht style file.

Here is a MWE
----------------------------
\documentclass[11pt]{scrbook}%ext
\usepackage{amsmath,mathtools,amssymb}
\begin{document}

\begin{center}
$\begin{array}{c}
y \left( x \right) ={x}^{2}+x+3\\ \relax%
\end{array}$
\end{center}
                   
\end{document}
----------------------

Compiled with

make4ht -ulm draft -c ./nma_mathjax.cfg foo.tex "htm,0,charset=utf-8" " -cunihtf -utf8"

Where nma_mathjax.cfg is

-----------------------------
\RequirePackage{mathjax-latex-4ht}
\Preamble{xhtml}
\begin{document}
\EndPreamble
-------------------------------

The HTML looks like this:

https://www.12000.org/tmp/relax/screen_shot.png

Using mathjax-latex-4ht.sty downloaded from

https://github.com/michal-h21/helpers4ht/blob/master/mathjax-latex-4ht.sty

Thank you,
--Nasser