text: Title: TQDM progress bars in jupyter notebooks do not appear in PDF via latex output 
  Body: - [X] I have marked all applicable categories:
      + [ ] exception-raising bug
      + [X] visual output bug
      + [ ] documentation request (i.e. "X is missing from the documentation." If instead I want to ask "how to use X?" I understand [StackOverflow#tqdm] is more appropriate)
      + [ ] new feature request
  - [X] I have visited the [source website], and in particular
    read the [known issues]
  - [X] I have searched through the [issue tracker] for duplicates
  - [X] I have mentioned version numbers, operating system and
    environment, where applicable:
    ```python
    import tqdm, sys
    print(tqdm.__version__, sys.version, sys.platform)
    ```
  gives:
  ```
  4.31.1 3.7.3 (default, Mar 27 2019, 22:11:17) 
  [GCC 7.3.0] linux
  ```
  
  When using the jupyter notebook extensions of TQDM, we get nice beautiful progress bars in the notebook, which is awesome. I'm currently writing some lectures for my students, and want to share a PDF version as well. But when I export to PDF via Latex, the progress bars are replaced by raw commands in the background like `HBox` (see attachment for an example)
  [tqdm_pdf_example.pdf](https://github.com/tqdm/tqdm/files/4466741/tqdm_pdf_example.pdf)
  
  It would be awesome if there was a way to get tqdm progress bars to show up in the latex output. I'm not sure if this is a tqdm or jupyter issue though. 
  
    [source website]: https://github.com/tqdm/tqdm/
    [known issues]: https://github.com/tqdm/tqdm/#faq-and-known-issues
    [issue tracker]: https://github.com/tqdm/tqdm/issues?q=
    [StackOverflow#tqdm]: https://stackoverflow.com/questions/tagged/tqdm
  