This was somehow possible already when the document was printed with
comments in margin before - but it was not possible to set this option
when exporting a PDF via dialog or API.
To use this setting via API, set the "ExportNotesInMargin" property.
Change-Id: I97a80c5b3b3b2cde669496fd881a41ea0acc5c28
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/143234
Tested-by: Jenkins
Reviewed-by: Samuel Mehrbrodt <samuel.mehrbrodt@allotropia.de>