Add prettier

[hosseinmd]

Is your proposal related to a problem?

Format documents

Describe the solution you'd like

I can run yarn add prettier, I know this.
Prettier is popular documents formatter and in front-end, There is no rival in this basin. React developers use it extensively. i think prettier should be in package.json.

Describe alternatives you've considered

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Additional context

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[petetnt]

HI @hosseinmd,

while Prettier is not included by default (it's a great tool, but CRA has always been by design very careful on adding extra tooling that not everyone might like) we have adding Prettier documented in the docs (thought it does not apply for Husky@^5 so it should be updated).