doc: minor fixes to advanced.docbook
doc: minor fixes to advanced.docbook

Thanks to Adrian Chaves Fernandez for the patch.

REVIEW:106033

hlamer/kate,jfmcarreira/kate,hlamer/kate,cmacq2/kate,sandsmark/kate,DickJ/kate,hlamer/kate,hlamer/kate,hlamer/kate,DickJ/kate,hlamer/kate,jfmcarreira/kate,hlamer/kate,hlamer/kate,jfmcarreira/kate,DickJ/kate,sandsmark/kate,DickJ/kate,cmacq2/kate,hlamer/kate,hlamer/kate,cmacq2/kate,sandsmark/kate,sandsmark/kate