man: improve --test documentation

Incorporates some suggestions from:

https://github.com/systemd/systemd/pull/12868#discussion_r296738370
https://github.com/systemd/systemd/commit/cd69e88ba3a692618048117b26fc9ea339aa1845#commitcomment-34060775

diff --git a/man/systemd.xml b/man/systemd.xml
index dfd77a474dab38e80745f726cf450c3e643417a1..77c6cc3dd7108960fbe083235f90f9a5c22d737a 100644 (file)
--- a/man/systemd.xml
+++ b/man/systemd.xml
@@ -71,12 +71,13 @@
         <term><option>--test</option></term>
 
         <listitem><para>Determine the initial start-up transaction (i.e. the list of jobs enqueued at
-        start-up), dump it and exit. This option is useful for debugging only. Note that during regular
-        service manager start-up further units might be started than this operation shows, because hardware,
-        socket, bus or other kinds of activation might add additional jobs. Use <option>--system</option> to
-        request the initial transaction of the system service manager (this is also the implied default),
-        combine with <option>--user</option> to request the initial transaction of the per-user service
-        manager instead.</para></listitem>
+        start-up), dump it and exit — without actually executing any of the determined jobs. This option is
+        useful for debugging only. Note that during regular service manager start-up additional units not
+        shown by this operation may be started, because hardware, socket, bus or other kinds of activation
+        might add additional jobs as the transaction is executed. Use <option>--system</option> to request
+        the initial transaction of the system service manager (this is also the implied default), combine
+        with <option>--user</option> to request the initial transaction of the per-user service manager
+        instead.</para></listitem>
       </varlistentry>
       <varlistentry>
         <term><option>--dump-configuration-items</option></term>