Fix typo

notes/notes.tex

@@ -231,7 +231,7 @@ Regole per documentarsi:
 \item \texttt{readlink}
 \end{itemize}
 
-\subsubsection{File System}
+\subsubsection{Text Processing}
 \begin{itemize}
 \item \texttt{cut} $\rightarrow$ \texttt{-f}, \texttt{-d}
 \item \texttt{paste} $\rightarrow$ \texttt{-d}