man: indicate that the JOB parameter to "systemctl cancel" is optional

As per:

https://social.treehouse.systems/@grawity/110376583742207755

diff --git a/man/systemctl.xml b/man/systemctl.xml
index 009aabacb9dc92d0e1198c7a26a917416be294a1..51ac818195273834145d5696896255bb26bbddac 100644 (file)
--- a/man/systemctl.xml
+++ b/man/systemctl.xml
@@ -1181,7 +1181,7 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           </listitem>
         </varlistentry>
         <varlistentry>
-          <term><command>cancel <replaceable>JOB</replaceable>…</command></term>
+          <term><command>cancel <optional><replaceable>JOB</replaceable>…</optional></command></term>
 
           <listitem>
             <para>Cancel one or more jobs specified on the command line