sphinx-doc: move to Python 3
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Sphinx was originally developed to generate documentation for CPython. Say whatever you want about Apple's inertia to move to Python 3, from my perspective when the Sphinx we ship cannot build CPython documentation (#33224), something is just wrong. Python 2.7 EOL is less than a year from now, the py27-based version cannot be shipped forever, so now is as good a time as any for switching. It's kinda ironic that `python@2` has its documentation built but the default `python` does not, due to `sphinx-doc` stuck with, guess what, python@2. (Edit: To be clear, I'm not proposing this change in order to bring docs to the `python` formula; I'm aware of the circular dependency. This PR is about pushing the ecosystem forward.)
Certain formulae that depends on `"sphinx-doc" => :build` might break if their Sphinx conf is still incompatible with Python 3 (shouldn't be hard to fix at all), or they insist on tapping into Sphinx from a python2.7 executable instead of just calling `sphinx-build`. But they really should up their game. Alternatively, a `sphinx-doc-python2` formula may be provided to keep those who are stuck in the past happy, but that's a really bad idea.
Actually I just coded up a quick example: https://github.com/jarun/googler/wiki/Directly-print-content-of-results-to-terminal. See if this is what you need. @ifohancroft
<img width="958" alt="screen shot 2019-01-19 at 9 26 24 pm" src="https://user-images.githubusercontent.com/4149852/51434563-b197c680-1c31-11e9-9603-f973508285c5.png">
Of course, you could also use a third-party content extraction library, or maybe a Readability-like web service to extract content from URLs. There are quite a few such libraries available in Python (can't think of names right off the top of my head, just Google), and probably even more in other languages. Since `BROWSER` and `--url-handler` are flexible enough, you can easily supply your own script to "show the chosen result directly in the terminal."
I fail to see why we should reinvent a textual web browser. There are even terminal web browsers that can render JavaScript and graphics, e.g. [browsh](https://www.brow.sh/).