Fix performance issue in Trans component

[pedrodurek]

Closes #1601

Identifying the source of the problem was challenging, but thanks to a reproducible example shared by @sebastien-comeau, I was able to identify the root cause.

By default, when the t function is not passed, the inferred value for KPrefix should be undefined. However, due to a TypeScript limitation, the KPrefix was not maintaining its default signature of undefined and instead was inferring all keys from the KeyPrefix. This caused the ParseKeys function to map over the entire list of keys and key prefixes in order to filter out the keys that started with every KPrefix value.

As a result, using the Trans component without specifying a KPrefix value could lead to an unnecessary exponential increase in the number of type inspections. This increase is due to the fact that ParseKeys would have to perform a large number of inspections for every possible combination of namespaces, keys, and key prefixes. Specifically, this increase in inspections can be characterized as Namespaces * Keys * Key Prefix.

To avoid this performance issue, I remove the constraint value from KPrefix (which, in this case, brings no benefit). By removing the constraint value, KPrefix maintains its default value (undefined) and avoids unnecessary inspections.

Checklist

• only relevant code is changed (make a diff before you submit the PR)
• run tests npm run test
• tests are included
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Checklist (for documentation change)

• only relevant documentation part is changed (make a diff before you submit the PR)
• motivation/reason is provided
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[coveralls]

coverage: 95.98%. remained the same when pulling e70f6ae on pedrodurek:fix-performance-issue-trans-component into 8fc3eec on i18next:master.

[adrai]

thank you... ❤️
included in v13.0.1