Don't use 'longtable' for collection of all keywords

With the way table content is organized into columns, it makes no sense to let this table be split across pages.

chapters/lexicalstructure.tex

@@ -109,7 +109,8 @@ \subsection{Modelica Keywords}\label{modelica-keywords}
 
 The following Modelica \emph{keywords} are reserved words and may not be
 used as identifiers, except as listed in \cref{lexical-conventions}:
-\begin{longtable}[c]{@{}lllll@{}}
+\begin{center}
+\begin{tabular}{l l l l l}
 \lstinline!algorithm! & \lstinline!discrete! & \lstinline!false! & \lstinline!loop! & \lstinline!pure!\\ \hline
 \lstinline!and! & \lstinline!each! & \lstinline!final! & \lstinline!model! & \lstinline!record!\\ \hline
 \lstinline!annotation! & \lstinline!else! & \lstinline!flow! & \lstinline!not! & \lstinline!redeclare!\\ \hline
@@ -121,8 +122,9 @@ \subsection{Modelica Keywords}\label{modelica-keywords}
 \lstinline!connector! & \lstinline!equation! & \lstinline!in! & \lstinline!parameter! & \lstinline!type!\\ \hline
 \lstinline!constant! & \lstinline!expandable! & \lstinline!initial! & \lstinline!partial! & \lstinline!when!\\ \hline
 \lstinline!constrainedby! & \lstinline!extends! & \lstinline!inner! & \lstinline!protected! & \lstinline!while!\\ \hline
-\lstinline!der! & \lstinline!external! & \lstinline!input! & \lstinline!public! & \lstinline!within!\\ \hline
-\end{longtable}
+\lstinline!der! & \lstinline!external! & \lstinline!input! & \lstinline!public! & \lstinline!within!\\
+\end{tabular}
+\end{center}
 
 \section{Literal Constants}\label{literal-constants}