add missing paren

network.tex

@@ -115,7 +115,7 @@
 for the textual database of port numbers and corresponding service names.
 \item To learn about networking and the Internet in general,
 see the Computer Networks (NSWI090) course.
-There are also on-line materials (\url{https://www.earchiv.cz/l226/index.php3}
+There are also on-line materials (\url{https://www.earchiv.cz/l226/index.php3})
 by ifdef([[[NOSPELLCHECK]]], [[[Ji\v{r}\'{i} Peterka]]]).
 \item \emph{IP} -- protocol of the internet layer within the TCP/IP network
 stack, provides data transfer between two interfaces identified by an IP