Fix LaTeX nested too deep error.

list_fix.tex

% source:
% http://jasonjuang.blogspot.co.il/2016/06/how-to-solve-too-deeply-nested-error.html
% http://www.texnia.com/archive/enumitem.pdf
% http://texdoc.net/texmf-dist/doc/latex/latex2e-help-texinfo/latex2e.pdf

\usepackage{enumitem}
\setlistdepth{20}
\renewlist{itemize}{itemize}{20}

% initially, use dots for all levels
\setlist[itemize]{label=$\cdot$}
\setlist[itemize]{labelsep=.5em}

% customize the first 3 levels
\setlist[itemize,1]{label=\textbullet}
\setlist[itemize,2]{label=--}
\setlist[itemize,3]{label=*}