Enhance doc search

[fpalombini]

Description

For https://datatracker.ietf.org/doc/search

It would be very useful if it would allow to combine search criteria (for example, I want all the docs in a certain WG with a certain state), instead of only allowing one criterion at the time.

In the same spirit, it would be good to be able to select several states (IESG states, ADs, areas etc) in the criteria that at the moment have dropdown menus.

Code of Conduct

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