Adding english plaintext jokes dataset
Hi @purvimisal, thanks for your contributions!

This jokes dataset has come up before, and after a conversation with the initial submitter, we decided not to add it then. Humor is important, but looking at the actual data points in this set raises several concerns :) 

The main issue is the Reddit part of the dataset which has most of the examples. A cursory look at the data shows a large number of highly offensive jokes that reproduce some pretty harmful biases (the second one from the top is a Holocaust joke). 

The other two sources have similar issues (especially the "Blond Jokes") to a slightly lesser extent.

While such datasets can be useful in the right context, there is a real concern that people using the library might miss some of this context (however much we outline it), and end up unwittingly training models that rely on some pretty racist and sexist associations.

We would recommend skipping this dataset altogether.

If you feel really strongly about having a joke dataset, then we would ask that you:
- remove the Reddit part of the dataset altogether
- write an in-depth description of the social biases present in the remaining data

Let us know which of the two you decide! And if you want recommendations on other datasets to add, hit us up on Slack 🤗  Hi @yjernite, thanks so much. I should've totally thought about this earlier. The harmful biases make so much sense. I should've consulted before making a PR. 
I will be closing this one and skipping this dataset altogether. 
Thanks again 

This PR adds a dataset of 200k English plaintext Jokes from three sources: Reddit, Stupidstuff, and Wocka.
Link: https://github.com/taivop/joke-dataset 

This is my second PR. 
First was: [#1269 ](https://github.com/huggingface/datasets/pull/1269)