fix wording

Author: Vladimir Kotal

proc.tex

@@ -408,7 +408,7 @@
 except for the following:
 \begin{itemize}
 \item The child process has a unique process and parent process ID.
-\item If the parent had multiple threads, the child will only have one that
+\item If the parent had multiple threads, the child will only have the one that
 called \texttt{fork}; will be further explained on page \pageref{FORKALL}.
 \item Child process resource utilization counters are set to 0.
 \item \texttt{alarm} settings and file locks are not inherited.