Fix text symbol error and hex error

[maicoleem]

Defines the TexSymbol class and fixes the error that does not find the hex attribute in the ChemWithName class

[NotCarlFriedrichGauss]

It's throwing ValueError: latex error converting to dvi. See log output above or the log file: media\Tex\4799158acc41e94f.log

``
[12/13/23 12:47:22] ERROR LaTeX compilation error: Argument of \skv_gob has an extra }. tex_file_writing.py:312

                ERROR    Context of error:                                                  tex_file_writing.py:346
                         \usepackage{amssymb}

                         -> \usepackage{chemfig}
                         \setchemfig{atom sep=2em,chemfig style=, atom style=,angle
                         increment=45,bond offset=2pt,double bond sep=2pt, node style=,
                         bond style=}
                         \begin{document}

[winterturtle1]

I'm also having the same issues with this latex error when converting to dvi when trying to run the example.

[NotCarlFriedrichGauss]

@winterturtle1 , refer https://discord.com/channels/581738731934056449/1184517679957159956 , its quite useful , kinda fixed my issue