systemctl: update documentation for --plain option

- Existing documentation did not mention that --plain omits the bullets and works on list-units and list-machines.

diff --git a/man/systemctl.xml b/man/systemctl.xml
index 36edc20..913e9e2 100644 (file)
--- a/man/systemctl.xml
+++ b/man/systemctl.xml
@@ -600,7 +600,9 @@
 
         <listitem>
           <para>When used with <command>list-dependencies</command>,
-          the output is printed as a list instead of a tree.</para>
+          <command>list-units</command> or <command>list-machines</command>, the
+          the output is printed as a list instead of a tree, and the bullet
+          circles are omitted.</para>
         </listitem>
       </varlistentry>