WIP FOR DISCUSSION: Templates: take PR Club content from YAML header

[harding]

Part of #1551

Upgrading the PR Review Club helper ({% include functions/detail-list.md %}) to Hugo is straightforward except for one point:

• Jekyll allows quoted strings to extend across line breaks, e.g.:

   {% include functions/detail-list.md
        q0="This is a question.
          This is more of the same question"
    %}
  

• Hugo requires all parts of a string to be on the same line, e.g.:

  {{< functions/detail-list.md
      q0="This is a question.  It must all be on the same line."
  >}}
  

It's trivial for me to go back and squash all previous review club entries to be on individual lines and to write a linter that enforces that for future review club entries. However, I like wrapping and we try to wrap everything else, so it would be a bit inconsistent. There are many possible alternative approaches (and I'm happy to discuss them), but one approach I think could be useful is for the Q&A to be written in YAML. This PR updates the most recent PR Review Club to use that approach, including providing template code that should exactly match our current layout.

Downsides:

• Q&A will need to be added to the header ("front matter") at the top of the file rather than inline with the location where it will appear

Upsides:

• Many text editors / IDEs can perform live syntax checks on YAML, hopefully allowing missing quotes, overquoting, or other problems to be caught earlier
• Easy conversion to Hugo or to any future site compiler we use

Comments @stickies-v @LarryRuane and others?

[stickies-v]

This new approach looks great to me, I think decoupling content from formatting is a nice improvement, so if this works well with Hugo it's absolutely a yes from me.

As commented, I would prefer keeping all the review club content in one place, but can work with either approach!

[harding]

Forced pushed to take all of @stickies-v suggestions. Thanks!

[harding]

Note, moving all of the review club content into the YAML header broke the recap_references_generator.rb logic, as it expected the name of the PR being reviewed to be the first link in the section starting on a line by itself.

Given the open discussion about how to port recap generator to Hugo, I'm just going to leave this PR open as-is for now and come back to it when we've decided what to do about the podcasts.