[Bug]: Supporting documents on secondary journallines saved as main documents

Describe the issue

If you on a journal batch have several lines with the same document number and date, and upload documents to each line, for instance travel expenses, then the posting routine will save each document as a "Main Attachment" rendering all the supporting documents invisible to the users.

Expected behavior

When using the same date and document number, the journal is aware that it is a main and supportive docuemnts. Expected behaviour is that the posted entry keeps this understanding.

Steps to reproduce

In the general journal create 2 lines with the same date and document number.
Upload Main attachment to line A, and another attachment as supporting attachment to line B.
Post Journal, and navigate to the posted entry.
The Incoming Document Files factbox will only show the Main document.

Additional context

Table 133 currently ends up having individual entry No. all marked as "Main document" instead of increasing Line No. as it does when attaching all documents to the same line.

I will provide a fix for a bug

• I will provide a fix for a bug

Start by reproducing the issue in the general journal with two lines sharing a date and document number, then inspect Table 133 and the journal posting routine. Check how attachments from separate lines are marked during posting and verify the posted entry's Incoming Document Files factbox shows both the main and supporting documents.