Initial spec draft (#28)

* Initial spec draft

* Update spec building

Enables biblio and spec linting

* Spec nits

* Update spec

ome small grammar changes, reusing `AsyncContextSnapshot()`, simplifying `AsyncContextSnapshot()`, simplifying `AsyncContext.prototype.run()`.

* Fixup!

* Remove constructor arg _name_

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Co-authored-by: Justin Ridgewell <[email protected]>

Author: legendecas