man: Fix spelling

man/sd_event_add_child.xml

@@ -100,7 +100,7 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
     being stopped by a signal), and <constant>WCONTINUED</constant>
     (watch for the child being resumed by a signal). See
     <citerefentry><refentrytitle>waitid</refentrytitle><manvolnum>2</manvolnum></citerefentry>
-    for futher information.</para>
+    for further information.</para>
 
     <para>Only a single handler may be installed for a specific
     child. The handler is enabled

man/sd_event_add_signal.xml

@@ -95,7 +95,7 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
     <structname>const struct signalfd_siginfo</structname> containing
     the information about the received signal. See
     <citerefentry><refentrytitle>signalfd</refentrytitle><manvolnum>2</manvolnum></citerefentry>
-    for futher information.</para>
+    for further information.</para>
 
     <para>Only a single handler may be installed for a specific
     signal. The signal will be unblocked, and must be

man/systemctl.xml

@@ -173,7 +173,7 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
           <para>Note that any <varname>After=</varname> dependency is
           automatically mirrored to create a
           <varname>Before=</varname> dependency. Temporal dependencies
-          may be specified explictly, but are also created implicitly
+          may be specified explicitly, but are also created implicitly
           for units which are <varname>WantedBy=</varname> targets
           (see
           <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>),