[docs] use sphinx :pep: role

[svenevs]

The Sphinx :pep: role can replace many of the manual links in the docs. It's been around since v1.0 (current docs require Sphinx>=1.4.4).

Would you all like me to finish replacing the rest of them? I noticed a broken PEP link on current stable docs, which is already fixed on latest. Using the :pep: may help prevent that in the future (not that it happens all that often...).

Note: there is a subtle difference, the hyperlink text becomes bold. Simulated:

• Previously: PEP 498
• With :pep: role: PEP 498

Files (to be) affected:

• ./docs/source/additional_features.rst
• ./docs/source/cheat_sheet_py3.rst
• ./docs/source/cheat_sheet.rst
• ./docs/source/command_line.rst
• ./docs/source/faq.rst
• ./docs/source/generics.rst
• ./docs/source/getting_started.rst
• ./docs/source/installed_packages.rst
• ./docs/source/introduction.rst
• ./docs/source/kinds_of_types.rst
• ./docs/source/more_types.rst
• ./docs/source/protocols.rst
• ./docs/source/python2.rst
• ./docs/source/python36.rst
• ./docs/source/stubgen.rst
• ./docs/source/stubs.rst

Misc:

• Keep the latest commit here that adds a linkcheck builder? I added it locally to assist me in addition to manual checking, but maybe this is something mypy will want to keep?
  • Sample build here: https://travis-ci.org/python/mypy/jobs/525100274

[gvanrossum]

Good idea — thanks! -- --Guido (mobile)

[hauntsaninja]

Thanks for bringing this up! I think this has since been subsumed by #7623