use docbook tag for option

diff --git a/bin/rndc/rndc.docbook b/bin/rndc/rndc.docbook
index f2f8fc04f1c6ca5a6795db536f40ac65328aa986..c67b8b7e75726c1548416517a333fdf9cfd308b3 100644 (file)
--- a/bin/rndc/rndc.docbook
+++ b/bin/rndc/rndc.docbook
@@ -368,7 +368,7 @@
        <listitem>
          <para>
            Sync changes in the journal file for a dynamic zone
-           to the master file.  If the "-clean" option is
+           to the master file.  If the <option>-clean</option> option is
            specified, the journal file is also removed.  If
            no zone is specified, then all zones are synced.
          </para>