Typos and minor changes needed for i18n issue template
The initial issue template (https://github.com/huggingface/transformers/pull/20199) includes minor typos and a closed PR link.
It makes it seem that the index page of a new language is already translated when it isn't.
Also some comment regarding what `langCode` or `langName` is would be helpful.

[ ] Fix typos.
[ ] Remove irrelevant PR link.
[ ] Explain what `langCode` or `langName` is more easily.
This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.