PEP 0: Make PEP titles in table clickable links

[CAM-Gerlach]

As requested by @gvanrossum in #2364 ,

FWIW the one usability improvement you could make in PEP 0 with the biggest effect would be to make PEP titles clickable. Having to aim at the little number in front of e.g. PEP 1 is awkward for someone with as clumsy a mouse as myself.

This PR does exactly that.

[hugovk]

Looks good! Please could you also update the docstring on line 24?

[CAM-Gerlach]

Please could you also update the docstring on line 24?

Sure, done.

[CAM-Gerlach]

Random side question @hugovk , but is there a reason the RTD deploy previews take so long (and provide relatively little feedback while they're building)? They take a full 3.5 minutes to generate and upload, which is over twice the time of the actual GH pages builds at 1.5 minutes (despite the latter using more rigorous, and thus slower, python and sphinx options), Using other services like Netlify, I've never had the deploy previews take more than a few seconds longer than the main build, and sometimes they were even faster (and I'm also used to much more real-time output than I'm seeing here).

[hugovk]

Looking at some logs:

• https://readthedocs.org/projects/pep-previews/builds/16366535/
• https://readthedocs.org/api/v2/build/16366535.txt

---

The slowest bit is the Sphinx build, and isn't using Sphinx's -j flag to build in parallel:

[rtd-command-info] start-time: 2022-03-15T01:08:14.980982Z, end-time: 2022-03-15T01:09:37.696641Z, duration: 82, exit-code: 0
/home/docs/checkouts/readthedocs.org/user_builds/pep-previews/envs/latest/bin/python -m sphinx -T -E -b dirhtml -d _build/doctrees -D language=en . _build/html
Running Sphinx v4.4.0

I see there's a SPHINX_PARALLEL feature flag we could ask RTD to enable:

• Use "-j auto" on sphinx-build command to build in parallel readthedocs/readthedocs.org#7128 (comment)

---

The next slowest is installing dependencies (RTD docs):

[rtd-command-info] start-time: 2022-03-15T01:07:41.295093Z, end-time: 2022-03-15T01:08:10.005945Z, duration: 28, exit-code: 0
/home/docs/checkouts/readthedocs.org/user_builds/pep-previews/envs/latest/bin/python -m pip install --upgrade --no-cache-dir mock==1.0.1 pillow==5.4.1 alabaster>=0.7,<0.8,!=0.7.5 commonmark==0.8.1 recommonmark==0.5.0 sphinx sphinx-rtd-theme readthedocs-sphinx-ext<2.2

One thing that sticks out there is the pillow==5.4.1 pin and we're running on Python 3.9. The first version to explicitly support Python 3.9 with prebuilt wheels is Pillow 8, so it's building 5.4.1 from source.

We can require dependencies in the config file but I think it installs those after the default ones. Worth a try though.

The newest Python supported by 5.4.1 is 3.7, and we need 3.9, so probably makes more sense to ask RTD to upgrade instead, or allow skipping it if not needed.

[CAM-Gerlach]

Thanks; I'm just used to having full control over the build environment, and it matching between my CIs, rather than it being managed for me. I assumed they'd install the project's deps from the same requirements file, but it seems like they are installing a whole heavy stack of others instead—and since they are managing it and pinning everything, and to old versions at that, I wonder why they aren't just cached in the environment?

I was previously in favor of standardizing on RTD, and hopefully at least some of these issues can get speedily resolved, but if not maybe we should consider switching to something like Netlify for the previews (and retain the existing GHP setup for deploy), which would offer the same preview functionality but allow us to run the exact same code we do in our GitHub Actions, for full control, speed and consistency between builders. But we should presumably defer any such decision until Adam gets back and we discuss it with the team and community.

[CAM-Gerlach]

As this is a straightforward tweak and its been 10 days, I'll go ahead and merge.