Doc: Duplicated Paragraphs in the Host Challenge section of the doc

There are duplicated paragraphs in the Host challenge section of the doc:

If you'd like to report a bug, please include the following information:
- the expected behaviour
There should be only a single occurence of this text:
```
We support two types of code-upload based challenges -

Code-Upload Based Challenge (without Static Dataset): These are usually reinforcement learning challenges which involve uploading a trained model in form of docker images and the environment is also saved in form of a docker image.
Static Code-Upload Based Challenge: These are challenges where the host might want the participants to upload models and they have static dataset on which they want to run the models and perform evaluations. This kind of challenge is especially useful in case of data privacy concerns.
```
- the observed behaviour
There are duplicated Paragraphs
- steps to reproduce the problem
- which operating system and/or browser you're using, if relevant
- (if possible) copies of the console/server logs

On the other hand, if you'd like to propose a new feature:
- please describe, as clearly as possible, what you'd like to see
- (if possible) include mockups/screenshots, if these would help convey the meaning better

Thanks!