repart: Make verity example more useful

Add Minimize= so the size gets calculated correctly and add a verity
signature partition as well for completeness.

man/repart.d.xml

@@ -831,10 +831,10 @@ SizeMaxBytes=64M
     </example>
 
      <example>
-      <title>Create a data and verity partition from a OS tree</title>
+      <title>Create a data partition and corresponding verity partitions from a OS tree</title>
 
       <para>Assuming we have an OS tree at /var/tmp/os-tree that we want to package in a root partition
-      together with a matching verity partition, we can do so as follows:</para>
+      together with matching verity partitions, we can do so as follows:</para>
 
       <para><programlisting># 50-root.conf
 [Partition]
@@ -842,6 +842,7 @@ Type=root
 CopyFiles=/var/tmp/os-tree
 Verity=data
 VerityMatchKey=root
+Minimize=guess
 </programlisting></para>
 
       <para><programlisting># 60-root-verity.conf
@@ -852,6 +853,14 @@ VerityMatchKey=root
 # Explicitly set the hash and data block size to 4K
 VerityDataBlockSizeBytes=4096
 VerityHashBlockSizeBytes=4096
+Minimize=best
+</programlisting></para>
+
+<para><programlisting># 70-root-verity-sig.conf
+[Partition]
+Type=root-verity-sig
+Verity=signature
+VerityMatchKey=root
 </programlisting></para>
     </example>