Add codespell support (config, workflow to detect/not fix) and make it fix some typos (#253)

* Add github action to codespell master on push and PRs

* Add rudimentary codespell config

* Ignore latex \@ constructs

* [DATALAD RUNCMD] chore: run codespell throughout fixing a few  new typos automagically

=== Do not change lines below ===
{
 "chain": [],
 "cmd": "codespell -w",
 "exit": 0,
 "extra_inputs": [],
 "inputs": [],
 "outputs": [],
 "pwd": "."
}
^^^ Do not change lines above ^^^

manual/moderncv_userguide.tex

@@ -405,7 +405,7 @@ In case BibTeX is used, the bibliography settings are adjusted in the lines
   % \renewcommand*{\bibliographyitemlabel}{[\arabic{enumiv}]}
   % \renewcommand{\refname}{Articles}
 
-  % bibliography with mutiple entries
+  % bibliography with multiple entries
   % \usepackage{multibib}
   % \newcites{book, misc}{{Books}, {Others}}
 \end{lstlisting}
@@ -492,7 +492,7 @@ This can be combined with the \code{itemize} environment.
     \cvcolumn[<width>]{<content>}
   \end{cvcolumns}
 \end{lstlisting}
-\code{<width>} is a number between 0 and 1 controling the width of the column.
+\code{<width>} is a number between 0 and 1 controlling the width of the column.
 
 \subsubsection{Skill matrix macros}
 The skill matrix is a table for displaying skills such as computer skills or project management skills graphically.