fix typo

doc/manual/manual.tex

@@ -4192,7 +4192,8 @@ \subsubsection{Installing parameter-GUI}
 to the directory that contains the parameter-GUI executable (optional). 
 This will allow \aspect{} to automatically enable the GUI during configuration.
 \end{enumerate}
-On a mac machine with recent macOS Sierra 10.12.4, Qt development libraries of version 4.x.x at the libraries' official website  \url{https://www.qt.io/download-open-source/} may fail to install.  Alternatively, you can install \texttt{qt4} through Homebrew (also see instruction here \url{https://github.com/cartr/homebrew-qt4})
+
+\paragraph{Installing on macOS} On a mac machine with recent macOS Sierra 10.12.4, Qt development libraries of version 4.x.x at the libraries' official website \url{https://www.qt.io/download-open-source/} may fail to install.  Alternatively, you can install \texttt{qt4} through Homebrew (also see instruction here \url{https://github.com/cartr/homebrew-qt4})
 \begin{verbatim}
 brew tap cartr/qt4
 brew tap-pin cartr/qt4
@@ -4203,7 +4204,7 @@ \subsubsection{Installing parameter-GUI}
 sudo port install qt4-mac
 \end{verbatim}
 Then you can follow the Linux user instructions provided previously to download and install dealii parameter-GUI. 
-Before running \texttt{cmake .}, you many need to either pass the path of \texttt{qt4} and specify the value of variable \texttt{QT\_LIBRARIES} to the directory that contains the libraries of \texttt{qt4}
+Before running \texttt{cmake .}, you may need to either pass the path of \texttt{qt4} and specify the value of variable \texttt{QT\_LIBRARIES} to the directory that contains the libraries of \texttt{qt4}
 or add those information into your \texttt{.bash\_profile}. For example, for installation through Mac Ports, you can set the following into your \texttt{.bash\_profile}
 \begin{verbatim}
 export PATH="$PATH:/opt/local/libexec/qt4"