[doc] nested markup is invalid in rst
Apparently nested markup in RST is invalid: https://docutils.sourceforge.io/FAQ.html#is-nested-inline-markup-possible

So currently this line doesn't get rendered properly, leaving inner markdown unrendered, resulting in:
```
You can create a model repo directly from `the /new page on the website <https://huggingface.co/new>`__.
```

This PR removes the bold markdown which fixes the link.

@sgugger 