FIx some malformed XML in option descriptions

E.g. these were using "<para>" at the *end* of a description. The real
WTF is that this is possible at all...

nixos/modules/services/backup/znapzend.nix

@@ -7,28 +7,23 @@ let
 
   planDescription = ''
       The znapzend backup plan to use for the source.
-    </para>
-    <para>
+
       The plan specifies how often to backup and for how long to keep the
       backups. It consists of a series of retention periodes to interval
       associations:
-    </para>
-    <para>
+
       <literal>
         retA=>intA,retB=>intB,...
       </literal>
-    </para>
-    <para>
-    Both intervals and retention periods are expressed in standard units
-    of time or multiples of them. You can use both the full name or a
-    shortcut according to the following listing:
-    </para>
-    <para>
+
+      Both intervals and retention periods are expressed in standard units
+      of time or multiples of them. You can use both the full name or a
+      shortcut according to the following listing:
+
       <literal>
         second|sec|s, minute|min, hour|h, day|d, week|w, month|mon|m, year|y
       </literal>
-    </para>
-    <para>
+
       See <citerefentry><refentrytitle>znapzendzetup</refentrytitle><manvolnum>1</manvolnum></citerefentry> for more info.
   '';
   planExample = "1h=>10min,1d=>1h,1w=>1d,1m=>1w,1y=>1m";
@@ -139,12 +134,10 @@ let
           type = nullOr ints.u16;
           description = ''
               Port to use for <command>mbuffer</command>.
-            </para>
-            <para>
+
               If this is null, it will run <command>mbuffer</command> through
               ssh.
-            </para>
-            <para>
+
               If this is not null, it will run <command>mbuffer</command>
               directly through TCP, which is not encrypted but faster. In that
               case the given port needs to be open on the destination host.