Related: fdo#74875 Filter of "nowiki" to be improved - Export to MediaWiki

<nowiki> mustn't be called almost everytime. Now this part still need some work (rework?)

Change-Id: I9a01c1e2fb51a51e0737296117db892e3b3b9ce6
Reviewed-on: https://gerrit.libreoffice.org/8024
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>