[Feature Request] Allow custom snippets (besides LaTeX)

[Dragoods]

I found "Text Snippets" is a good complement to user-defined snippets, but it is out-of-date, no preview and awkward trigger hotkey.

Because I often use multiline templates, say

\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
% Template
\end{tikzpicture}
\end{document}

Is there a way to implement such multiline-replacement, or can you add something like this please?