\documentclass[11pt,a4paper]{article}
\usepackage[top=1.3cm,bottom=2cm,left=1.5cm,right=1.5cm]{geometry}

\usepackage{calc}
\usepackage{graphicx}
\usepackage{xcolor}
\usepackage{color}
\usepackage{colortbl}
\usepackage{multirow}
\usepackage{hanging}
\usepackage[english]{babel} % Language package
\usepackage{tikz} % Draw things
\usepackage{ltablex} % Multipage tables
\usepackage{float} % Positioning figures
\usepackage{wrapfig} % Wraps text around figures
\usepackage{array}
% \usepackage{booktabs}
\usepackage{fancyhdr} % Fancy headers and footers
\pagestyle{fancy}
\counterwithin{table}{section}
\usepackage{tocloft}
\usepackage{booktabs}
\usepackage{csquotes}
\usepackage{biblatex}
\usepackage{mathtools} % More math tools, goes with amsmath below
\usepackage[normalem]{ulem}
\usepackage{enumitem}
\usepackage{amssymb,amsmath} %MAthematical symbols in latex
\usepackage{siunitx}
\usepackage[
  colorlinks  = true,
  urlcolor    = blue,
  citecolor   = red,
  linkcolor   = red % Sets the color of links in general
]{hyperref}

% Settings
\author{$authors$}
\date{$date$}
\lhead{$authors$}
\rhead{$course$: $title$}
\addbibresource{$bibliography$} % Set path to bibfile
\setlength{\parindent}{4em} %Identation paragraphs
\setlength{\parskip}{1em} % Paragraph spacing
\renewcommand{\baselinestretch}{1.0} %Interligne
\interfootnotelinepenalty=10000 %% Completely prevent breaking of footnotes
\setlength{\headheight}{25pt} % Headheight
\numberwithin{equation}{section} % Numbering equations

\renewcommand{\headrulewidth}{0.5pt} % Line delemiting the header
\renewcommand{\cftsecleader}{\cftdotfill{\cftdotsep}}
\renewcommand{\cftsecfont}{\itshape}
\providecommand{\tightlist}{%
  \setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}

% Define CSL environment
\newlength{\cslhangindent}
\setlength{\cslhangindent}{1.5em}
\newenvironment{CSLReferences}%
{\setlength{\parindent}{0pt}%
\everypar{\setlength{\hangindent}{\cslhangindent}}\ignorespaces}%
{\par}

%Define float placement.
\makeatletter\renewcommand*{\fps@figure}{H}\makeatother

% Define standard fig width, need the graphix package for that
\setkeys{Gin}{width=.75\textwidth}

% Define Shaded environment for correct knitting
$if(highlighting-macros)$
$highlighting-macros$
$endif$

% Print whole bibliography
\nocite{*}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}

\thispagestyle{plain}
\title {\textbf{$course$: $title$}} 
\author {$authors$}
\maketitle
\pagenumbering{arabic}
\makeatletter
\renewcommand*\env@matrix[1][*\c@MaxMatrixCols c]{%
  \hskip -\arraycolsep
  \let\@ifnextchar\new@ifnextchar
  \array{#1}}
\makeatother

$body$

\end{document}