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/ukify.xml

@@ -606,7 +606,7 @@
       --linux=/lib/modules/6.0.9-300.fc37.x86_64/vmlinuz \
       --initrd=/some/path/initramfs-6.0.9-300.fc37.x86_64.img \
       --cmdline='quiet rw'
-      </programlisting>
+</programlisting>
 
       <para>This creates an unsigned UKI <filename>./vmlinuz.unsigned.efi</filename>.</para>
     </example>
@@ -632,7 +632,7 @@
       --secureboot-certificate=sb.cert \
       --sign-kernel \
       --cmdline='quiet rw rhgb'
-      </programlisting>
+</programlisting>
 
       <para>This creates a signed UKI <filename index='false'>./vmlinuz.signed.efi</filename>.
       The initrd section contains two concatenated parts, <filename index='false'>early_cpio</filename>
@@ -676,7 +676,7 @@ Phases=enter-initrd:leave-initrd
 $ ukify -c ukify.conf build \
         --linux=/lib/modules/6.0.9-300.fc37.x86_64/vmlinuz \
         --initrd=/some/path/initramfs-6.0.9-300.fc37.x86_64.img
-      </programlisting>
+</programlisting>
 
       <para>One "initrd" (<filename index='false'>early_cpio</filename>) is specified in the config file, and
       the other initrd (<filename index='false'>initramfs-6.0.9-300.fc37.x86_64.img</filename>) is specified
@@ -694,7 +694,7 @@ $ ukify -c ukify.conf build \
       --sbat='sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
       uki-addon.author,1,UKI Addon for System,uki-addon.author,1,https://www.freedesktop.org/software/systemd/man/systemd-stub.html'
       --output=debug.addon.efi
-      </programlisting>
+</programlisting>
 
       <para>This creates a signed PE binary that contains the additional kernel command line parameter
       <literal>debug</literal> with SBAT metadata referring to the owner of the addon.</para>
@@ -738,7 +738,7 @@ Writing public key for PCR signing to /etc/systemd/tpm2-pcr-public-key-system.pe
       <programlisting>$ ukify build \
       --profile='TITLE=Base' \
       --output=profile0.efi
-      </programlisting>
+</programlisting>
 
       <para>Add a second profile (@1):</para>
 
@@ -747,7 +747,7 @@ Writing public key for PCR signing to /etc/systemd/tpm2-pcr-public-key-system.pe
 ID=storagetm' \
       --cmdline='quiet rw rd.systemd.unit=stroage-target-mode.target' \
       --output=profile1.efi
-      </programlisting>
+</programlisting>
 
       <para>Add a third profile (@2):</para>
 
@@ -756,7 +756,7 @@ ID=storagetm' \
 ID=factory-reset' \
       --cmdline='quiet rw systemd.unit=factory-reset.target' \
       --output=profile2.efi
-      </programlisting>
+</programlisting>
 
       <para>Then, create a UKI and include all the generated profiles:</para>
 
@@ -768,7 +768,7 @@ ID=factory-reset' \
       --join-profile=profile1.efi \
       --join-profile=profile2.efi \
       --output=base.efi
-      </programlisting>
+</programlisting>
 
       <para>The resulting UKI <filename>base-with-profile-0-1-2.efi</filename> will now contain three profiles.</para>
     </example>