Improved Math (Latex) support

[mccann]

Features:

• Prevent Markdown processing inside $'s
• Allow multi-line Latex, like that supported by:
  • jupyter notebook
  • vscode
  • obsidian
  • probably many more - only tested the above.
• now prevents arbitrary html getting passed through

Newly supported examples:

This now works: $ \begin{bmatrix} 1 & 0 \[.25em] 0 & 1 \end{bmatrix} $

[sbarex]

Thanks for your support!