Co-authored-by: OH HYUN KEUN <ohhk@uitgis.com>

This upstreams some of the [introduction
post](reactwg/react-compiler#5) into the
docs since this knowledge is quite fundamental to understanding the
compiler, and it's confusing to not have it linked in the canonical
source for the docs. It also adds more information about
[debugging](reactwg/react-compiler#7) and
reorganizes a few sections to make things clearer

ghstack-source-id: ef32fc723722eb5119529abcc572dd2bcf2b1cab
Pull Request resolved: reactjs/react.dev#6895

* Add React Conf 2024 Recap post

* Spelling and links

* Apply suggestions from code review

Co-authored-by: lauren <poteto@users.noreply.github.com>

* Edits

* Edits

* better link

* Update date

* Update date and nits

* feedback

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Co-authored-by: lauren <poteto@users.noreply.github.com>

* Add codemods to upgrade guide

* Update src/content/blog/2024/04/25/react-19-upgrade-guide.md

Co-authored-by: Ahmed Abdelbaset <A7med3bdulBaset@gmail.com>

* Add benefits

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Co-authored-by: Ahmed Abdelbaset <A7med3bdulBaset@gmail.com>

The docs for stylesheet precedence incorrectly state that there is an enumerated set of valid precedences. This is incorrect. The precedence value can be anything and React infers the hierarchy from the order in which it discovers precedences

* FIX: Typo in useEffect.md caveats

* Fix another typo

* Add act documentation

* Update structure based on feedback

* Add usage examples and async act

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Co-authored-by: Rick Hanlon <rickhanlonii@fb.com>

Fix very minor typo