pdf documentation is not bookmarked

The last PDF documentation 1.0.1. (Feb 05, 2020) has no table of contents, no bookmarks.   

I made Contents in the form of bookmarks, meanwhile up to level 2.  
The edited (bookmarked) pdf file is here: [pandas.pdf](https://github.com/pandas-dev/pandas/files/4303229/pandas.pdf).
