Add code block option to disable line numbers

[philippemilink]

Hello,

Suggested by a Zeste de Savoir user, it would be nice if in addition to hl_lines and linenostart, we could have an option to disable line numbering when rendering code blocks.

[StaloneLab]

Why not. HTML part should be quite easy to do (check meta property in custom zmarkdown/utils/code-handler.js code handler), but this requires change to the template for PDF, as we currently have no way to disable numbering on LaTeX side.