man: drop whitespace from final <programlisting> lines

In the troff output, this doesn't seem to make any difference. But in the
html output, the whitespace is sometimes preserved, creating an additional
gap before the following content. Drop it everywhere to avoid this.

man/systemd-analyze.xml

@@ -271,7 +271,7 @@ multi-user.target reached after 47.820s in userspace
             23ms sysroot.mount
             11ms initrd-udevadm-cleanup-db.service
              3ms sys-kernel-config.mount
-        </programlisting>
+</programlisting>
       </example>
     </refsect2>
 
@@ -670,7 +670,7 @@ NAutoVTs=8
 
 # /etc/systemd/logind.conf.d/50-override.conf
 ... some administrator override
-        </programlisting>
+</programlisting>
       </example>
     </refsect2>
 
@@ -716,7 +716,7 @@ $ systemd-analyze compare-versions 1 lt 2; echo $?
 0
 $ systemd-analyze compare-versions 1 ge 2; echo $?
 1
-        </programlisting>
+</programlisting>
       </example>
     </refsect2>
 
@@ -768,7 +768,7 @@ Error: org.freedesktop.systemd1.LoadFailed:
    No such file or directory.
 Failed to create user.slice/start: Invalid argument
 user.slice: man nosuchfile(1) command failed with code 16
-        </programlisting>
+</programlisting>
       </example>
 
       <example>
@@ -787,7 +787,7 @@ Accept=yes
 $ systemd-analyze verify ./a.socket ./b.socket
 Service a.service not loaded, a.socket cannot be started.
 Service b@0.service not loaded, b.socket cannot be started.
-        </programlisting>
+</programlisting>
       </example>
 
       <example>
@@ -807,7 +807,7 @@ Failed to prepare filename /tmp/source: Invalid argument
 
 $ systemd-analyze verify /tmp/source:alias.service
 alias.service:7: Unknown key name 'MysteryKey' in section 'Service', ignoring.
-        </programlisting>
+</programlisting>
       </example>
 
     </refsect2>
@@ -886,7 +886,7 @@ alias.service:7: Unknown key name 'MysteryKey' in section 'Service', ignoring.
                 "buildId" : "b5e428254abf14237b0ae70ed85fffbb98a78f88"
         }
 }
-        </programlisting>
+</programlisting>
       </example>
     </refsect2>
 
@@ -1762,7 +1762,7 @@ io.systemd.credential:vmm.notify_socket=vsock-stream:2:254570042
     "range": 1
     }
 }
-      </programlisting>
+</programlisting>
     </example>
   </refsect1>