docs: Fix whitespace in output

Many moons ago, commit id '8d7800a5' adjusted the format of the output
to add a space on the HEADER and the DATA... the docs weren't updated to
reflect that... This makes that adjustment.

docs/formatsecret.html.in

@@ -123,9 +123,9 @@
       Secret 1b40a534-8301-45d5-b1aa-11894ebb1735 created
       #
       # virsh secret-list
-      UUID                                 Usage
+       UUID                                 Usage
       -----------------------------------------------------------
-      1b40a534-8301-45d5-b1aa-11894ebb1735 cephx ceph_example
+       1b40a534-8301-45d5-b1aa-11894ebb1735 cephx ceph_example
       #
       # CEPHPHRASE=`printf %s "pass phrase" | base64`
       # virsh secret-set-value 1b40a534-8301-45d5-b1aa-11894ebb1735 $CEPHPHRASE
@@ -209,9 +209,9 @@
       Secret c4dbe20b-b1a3-4ac1-b6e6-2ac97852ebb6 created
 
       # virsh secret-list
-      UUID                                 Usage
+       UUID                                 Usage
       -----------------------------------------------------------
-      c4dbe20b-b1a3-4ac1-b6e6-2ac97852ebb6 iscsi libvirtiscsi
+       c4dbe20b-b1a3-4ac1-b6e6-2ac97852ebb6 iscsi libvirtiscsi
 
       # MYSECRET=`printf %s "mysecret" | base64`
       # virsh secret-set-value c4dbe20b-b1a3-4ac1-b6e6-2ac97852ebb6 $MYSECRET