docs: Clarify systemctl show manual

The manual incorrectly asserted that the properties in systemctl show
matched the the options in systemd-system.conf, which is not always true.

Add clarification on the equivalence of the properties in systemctl show
and systemd-system.conf

Fixed #21230

diff --git a/man/systemctl.xml b/man/systemctl.xml
index b6be21ed877e55394bc1f553743ee32c99aa19ae..1c149095239e3e5d0bfe9aa7efec8826c3693478 100644 (file)
--- a/man/systemctl.xml
+++ b/man/systemctl.xml
@@ -1660,8 +1660,8 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           completion is implemented for property names.</para>
 
           <para>For the manager itself,
-          <command>systemctl show</command> will show all available
-          properties. Those properties are documented in
+          <command>systemctl show</command>
+          will show all available properties, most of which are derived or closely match the options described in
           <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
           </para>