🚀 Feature Proposal / Possible bug fix

Hi there!

Proposals (all of which I can open a PRs for, if desired):

1. Allow i18nIsDynamicList to function correctly, even when child is not a list.
2. Rename i18nIsDynamicList to i18nIsDynamicContent (will be done in a backwards compatible way, i.e. both will exist for a time, maybe till v14)

Motivation

1. I believe this first proposal is actually a bugfix. Currently, the Trans component assumes that the child of an element with the i18nIsDynamicList prop is a list, which may not be the case. See the following example:

const someDynamicVar = cond ? <Comp /> : 'Text';

<Trans>
  Hi there,{' '}
  <React.Fragment i18nIsDynamicList>
    {someDynamicVar}
  </React.Fragment>
</Trans>

The above will not render correctly. However, the following does:

const someDynamicVar = cond ? <Comp /> : 'Text';

<Trans>
  Hi there,{' '}
  <React.Fragment i18nIsDynamicList>
    <></>
    {someDynamicVar}
  </React.Fragment>
</Trans>

By adding a fragment, the child becomes a list, and therefore the content renders correctly. My proposal is to make it work without the need for a list.

2. If we make the above change, which seems to me to be a bugfix, it would make sense to rename the i18nIsDynamicList prop to something that better describes what it's for. I was thinking i18nHasDynamicChildren. We can make this change in a backwards compatible way (i.e. both i18nIsDynamicList and i18nHasDynamicChildren will exist for a time, maybe till v14)

Please let me know if these changes are welcome, in which case I'll make a PR!