tree-wide: use normal spelling of "reopen"

It's a commonly used verb meaning "to open again".

man/systemd.exec.xml

@@ -3017,7 +3017,7 @@ SystemCallErrorNumber=EPERM</programlisting>
         the kernel log buffer, the unit will implicitly gain a dependency of type <varname>After=</varname>
         on <filename>systemd-journald.socket</filename> (also see the "Implicit Dependencies" section
         above). Also note that in this case stdout (or stderr, see below) will be an
-        <constant>AF_UNIX</constant> stream socket, and not a pipe or FIFO that can be re-opened. This means
+        <constant>AF_UNIX</constant> stream socket, and not a pipe or FIFO that can be reopened. This means
         when executing shell scripts the construct <command>echo "hello" &gt; /dev/stderr</command> for
         writing text to stderr will not work. To mitigate this use the construct <command>echo "hello"
         >&amp;2</command> instead, which is mostly equivalent and avoids this pitfall.</para>