[doc][handbook] fix typo

doc/handbook/4_developingdumux.tex

@@ -40,13 +40,13 @@ more information.
 \Dune and \Dumux are built with the help of \texttt{dunecontrol}, as explained on page \pageref{buildIt}.
 Per default, \Dumux is compiled using optimization options, which leads to faster runtimes but is unsuitable
 for debugging. For debug opts you can set \texttt{DCMAKE_BUILD_TYPE} to \texttt{Debug} or \texttt{RelWithDebInfo}
-in your options file. You can also do this in any of the \texttt{CMakeLists.txt} in Dumux by adding
+in your options file. You can also do this in any of the \texttt{CMakeLists.txt} in Dumux by adding:
 
 \begin{lstlisting}[style=Shell]
 set(CMAKE_BUILD_TYPE Debug)
 \end{lstlisting}
 
-Afterwarde rerun cmake again (run cmake <path-to-build-dir>).
+Afterwards rerun cmake again (run cmake <path-to-build-dir>).
 
 \paragraph{Dunecontrol for selected modules}
 A complete build using \texttt{dunecontrol} takes some time. In many cases not all modules need to be re-built.