feature: custom latex template

[yuukibarns]

Did you check the docs?

• [x] I have read all the snacks.nvim docs

Is your feature request related to a problem? Please describe.

High appreciation for this wonderful plugin, it helps me a lot.

But somehow I find commutative diagrams inside tikz-cd environment are not rendered, after checking the latex files in the cache, I find the current template does not use tikz-cd package.

    img.content = ([[
\documentclass[preview,border=2pt,varwidth]{standalone}
\usepackage{xcolor, amsmath, amssymb}
\begin{document}
{ \large \color[HTML]{%s}
%s}
\end{document}
    ]]):format(fg:upper():sub(2), content)

Describe the solution you'd like

Simply adding it can solve my problem,

Describe alternatives you've considered

but I think for variety of users the demand are different, so maybe can add an option for custom latex template?

Additional context

No response