Translation into Swift Concurrency model#1

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DougGregor wants to merge 9 commits intoxcode-12-2-beta-3from

xcode-12-2-beta-3-concurrency

Commits on Oct 15, 2020

Translation into Swift Concurrency model
DougGregor
committed

Commits on Oct 21, 2020

[Concurrency] Drop "get" prefix when importing Objective-C methods as async.
DougGregor
committed

Commits on Oct 22, 2020

[Concurrency] Drop "Asynchronously" suffix from imported 'async' methods.
DougGregor
committed

Commits on Oct 23, 2020

[Concurrency] Retain text from a completion-handler selector piece.
DougGregor
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Commits on Oct 30, 2020

Implicitly strip optionals for return type of translated "async throws".
DougGregor
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Commits on Nov 10, 2020

[Concurrency] Avoid importing 'async' overloads.
DougGregor
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Commits on Nov 11, 2020

Append "Async" suffix to imported async methods with nullable completion handlers.
DougGregor
committed

Commits on Dec 8, 2020

Update translation for recent heuristic tweaks
DougGregor
committed

Commits on Dec 11, 2020

Remove all of the @asyncHandlers.
DougGregor
committed