Add page_number in the pdf_content_list.json

[CathZheng]

Hi, I'm trying to use the pdf_content_list.json for further processing. I want to use the page number as a reference back to the original pdf. Is there anyway I can have the page_number for each element in the json. Right now I only have something like:
{
"type": "text",
"text": "Hello",
"text_level": 1
}
I saw that in the preprocess files there is page_ID, how can I add it to the content list?

[myhloli]

added in master.