So I just found "User > Customize Completion" in texmaker and it seemed great. Quite soon I run into the problem with defining macros that span several lines.
I am able to get:
\begin{figure}[•] \centering \includegraphics[width=\linewidth]{•}
\end{figure}
but I would like:
\begin{figure}[•]
\centering
\includegraphics[width=\linewidth]{•}
\end{figure}
And maybe even an indent within the figure environment. As a frequent user of Overleaf I have grown used to being able of having this kind of auto-completion. Is it possible to configure?