Update @woo…/currency code docs, define & export type declarations.

[tomalec]

⚠️ This PR is based on/requires #7840
And served the same purpose:

As per the Dependency Extraction Webpack Plugin installing this package in another plugin serves only type checking purposes (see WordPress/gutenberg#35630 (comment)), it would be beneficial to actually define and export those types.

• Removes unrelated Google Search link form README (1c4c8b4)
• Defines CurrencyConfig type, exports declarations (afa01e3)
  So they could be referenced in the other packages.

Accessibility

n/a - its only code documentation change

Screenshots

Detailed test instructions:

• npm install @woocommerce/currency
• Somewhere in your codebase's JSDoc use {import('@woocommerce/currency').CurrencyConfig}

Additional notes:

1. This data type could be used further in @woocommerce/wc-admin-settings to make the code docs shorter.

2. Preferable I'd not define CurrencyProps type, just do

   /**
    * @typedef {NumberConfig} CurrencyConfig
    * @property {string} code Currency ISO code.
    * …

   or at least

   /**
    * @typedef {NumberConfig & {code: string}} CurrencyConfig
    * @property {string} code Currency ISO code.
    * …

   But unfortunately, it's not supported by TypeScript yet Support typedef inheritance with JSDoc microsoft/TypeScript#20077

3. The type of the object returned by CurrencyFactory is still not defined, and the individual methods of that object are lost as well. I'd solve that in a separate PR, as I believe we could do a small refactoring by the way. The current code base makes it hard to document and test it. At least that makes this PR shorter and less controversial.

---

No changelog necessary - added entry in package's one.

[tomalec]

We can make it

Suggested change

	* @typedef {Object} CurrencyProps
	* @typedef {NumberConfig} CurrencyConfig

It's valid JSDoc, but TypeScirpt is not able to parse it microsoft/TypeScript#20077

Or we can make it

* @typedef {NumberConfig & { code: string, … } } CurrencyProps

But then we lose definitions of the extra props.

[github-actions]

This PR has been automatically marked as stale because it has not had any recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions]

This PR was automatically closed due to being stale.

[tomalec]

I'm not sure if we can make it before the merge, but if #7840 lands it would be nice to have this as well.

[tomalec]

Closing in favor of woocommerce/woocommerce#32337