Support list autocontinuation

[avonmoll]

Maybe this is more work than it's worth, but I really like markdown-writer's list autocontinuation.

E.g. pressing Enter when the cursor is at the end of the \item First line continues the list on the following line:

\begin{itemize}
  \item First|
\end{itemize}

(Enter)

\begin{itemize}
  \item First
  \item |
\end{itemize}

[Focus]

Pretty neat idea