docs/conf.py: Use https for link to docs.python.org.

[pfalcon]

To get rid of warning saying there's redirect from http: to https:.

[dpgeorge]

I'm not opposed to this change, but I don't see any warnings when linking through to the CPython docs. These links already seem to be https. Eg the CPython gc link on this page: http://docs.micropython.org/en/latest/library/gc.html

[pfalcon]

Weird. I now don't see it too, but I swear there was a red-ansi-escaped warning for it. Now I just see:

loading intersphinx inventory from http://docs.python.org/3.5/objects.inv...
intersphinx inventory has moved: http://docs.python.org/3.5/objects.inv -> https://docs.python.org/3.5/objects.inv

It's Sphinx v1.6.7 here. Well, it shouldn't hurt to apply this, avoiding extra HTTP roundtrip on each doc generation.

[dpgeorge]

Ok, merged in 42d0a28