Correct caching warning footnote about 'no-cache' (#18763)
Correct caching warning footnote about 'no-cache' (#18763)

* Correct caching warning footnote about 'no-cache'

Footnote was incorrectly warning against using 'no-cache', and could use a little additional clarification.

[1]: https://tools.ietf.org/html/rfc7234#section-5.2.2.1
[2]: https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/http-caching#no-cache_and_no-store

* run prettier

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