Add import statements to tutorials

[jugmac00]

Feature request

• A description of the feature you would like to have

I suggest to add the import statements to the tutorial sections.

• If relevant, the context that you are in. What are you trying to achieve?

I am a new user of pdfminer.six (wohoo) and I tried to follow the tutorial, but had a hard time as the import statements are missing.

eg here https://pdfminersix.readthedocs.io/en/latest/tutorial/highlevel.html

I certainly have found the excellent API documentation later, but it took some time.

Also, when I had a look in the source code of the docs, I saw that there is a test setup directive included in order to make the doc tests pass.

.. testsetup::

    import sys
    from pdfminer.high_level import extract_text_to_fp, extract_text

So, doc tests need import statements, humans (at least beginners) need import statements, why not include them in the tutorial sections?

I'd like to create a PR if you are ok with my suggestion.

[pietermarsman]

Thanks for the tip! :+1: