Fix duplicate keys in NewsQA
Flaky tests? Thanks for your contribution, @bryant1410.

I think the fix of the duplicate key in this PR was superseded by:
- #3696

I'm closing this because we are moving all dataset scripts from GitHub to the Hugging Face Hub.
* Fix duplicate keys in NewsQA when loading from CSV files.
* Fix s/narqa/newsqa/ in the download manually error message.
* Make the download manually error message show nicely when printed. Otherwise, is hard to read due to spacing issues.
* Fix the format of the license text.
* Reformat the code to make it simpler.