Fix generix type declaration

[Khartir]

Description

Closes #227. Iirc the T extends {} was just a quick fix for the problem TS has parsing generic arrow functions in JSX files. @phryneas do you agree?

Breaking changes

None

Checklist

• Updated the TypeScript type definitions

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Sandbox	Source
mutable-sky-b54xf	Configuration
React Typescript	Issue #227

[codecov]

Codecov Report

Merging #229 into next will decrease coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##             next     #229      +/-   ##
==========================================
- Coverage   98.59%   98.58%   -0.01%     
==========================================
  Files           8        8              
  Lines         426      424       -2     
  Branches      140      140              
==========================================
- Hits          420      418       -2     
  Misses          6        6

Impacted Files	Coverage Δ
packages/react-async/src/useAsync.tsx	99.23% <100%> (-0.01%)	⬇️
packages/react-async/src/Async.tsx	100% <100%> (ø)	⬆️

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[ghengeveld]

Excellent! Thanks for the quick fix! We can ship this with v10.

[phryneas]

If it works, thumbs up 👍 otherwise, we could have extended unknown instead, but this is even better. Thansk!