[models website] search UI issues
@sshleifer showed me a secret API to finding all fsmt models: https://huggingface.co/models?filter=fsmt

I have several why/how questions:

1. Why can't I do the same from the models page? Where does a user find access to the `filter=` key? It's the `Tags` dropdown, but there is no way to choose the tag I want - `fsmt` is not in the options.

2. How can I use the UI to combine keywords/tags so that I could get sub-sets, like https://huggingface.co/models?filter=fsmt&filter=allenai or perhaps https://huggingface.co/models?search=allenai&filter=fsmt?

3. I don't think `filter` can be repeated. If I reverse order: https://huggingface.co/models?filter=allenai&filter=fsmt I get different results from https://huggingface.co/models?filter=fsmt&filter=allenai - so it ignores the second key (this is sub-set related)

4. The left upper corner widget appears very unintuitive - it looks like a search input, it even says "Search", but it only does something (shows a dropdown list of choices) if the input matches something it finds behind the scenes. So if I type `fsmt` it just sits there quietly. I should be able to hit enter and it to tell me that it found nothing or something like that. Silence is not a great UI. 

5. Why doesn't that search widget in the left upper corner find `fsmt`? What fields does it search?

Thank you.

@julien-c 
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
<|||||>Unstale - would be great to have some of these resolved.<|||||>This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
