docs: Deprecate use of git.io URL shortener

[matthewfeickert]

Description

GitHub is killing off the git.io URL shortening service this Friday (2022-04-29) so all URLs in the docs that use it need to be updated.

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• Tests are passing
• "WIP" removed from the title of the pull request
• Selected an Assignee for the PR to be responsible for the log summary

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* Replace all instances of git.io shortened URLs with full URLs as git.io is
being killed off by GitHub on 2022-04-29.
   - c.f. https://github.blog/changelog/2022-04-25-git-io-deprecation/

[matthewfeickert]

@kratsg if you have a favorite URL shortener that we can rely on to be stable for a long time to come it would be good to switch to that instead of using the full URLs.

[codecov]

Codecov Report

Merging #1851 (115b437) into master (afa49e0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1851   +/-   ##
=======================================
  Coverage   98.16%   98.16%           
=======================================
  Files          68       68           
  Lines        4315     4315           
  Branches      725      725           
=======================================
  Hits         4236     4236           
  Misses         46       46           
  Partials       33       33           

Flag	Coverage Δ
contrib	26.44% <ø> (ø)
doctest	60.78% <ø> (ø)
unittests-3.10	96.03% <ø> (ø)
unittests-3.7	96.02% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/pyhf/cli/infer.py	97.61% <ø> (ø)

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[matthewfeickert]

Relevant RTD build pages:

• README: https://pyhf--1851.org.readthedocs.build/en/1851/index.html#hello-world
• CLI API: https://pyhf--1851.org.readthedocs.build/en/1851/cli.html#pyhf

[matthewfeickert]

@kratsg @lukasheinrich This doesn't look too bad and it turns out that we already use the full URL in other examples in the CLI API docs, so I think this is fine.

e.g.

pyhf/src/pyhf/cli/spec.py

Line 36 in afa49e0

$ curl -sL https://raw.githubusercontent.com/scikit-hep/pyhf/master/docs/examples/json/2-bin_1-channel.json | pyhf inspect