add page_number parameter to download all pages of pdf files

[geoffreyp]

The problem I'm solving is that you can only download the first page of the pdf documents in the global folder.

I've added a parameter to the global_dossier_api.get_document() method to download all the pages of a PDF file.

[parkerhancock]

Thanks for this contribution! A few issues I noticed:

1. The change only modifies the sync version - we should modify the async version in _async/uspto/global_dossier/ and regenerate the sync version via unasync.py

2. The current implementation passes self.pages (total page count) as the page number, which would request page N instead of downloading all pages 1 through N.

To download all pages, we'd need to either:

• Loop through pages 1 to self.pages and concatenate the PDFs
• Or change the API call approach

Would you be able to update the PR to address these issues?