feat: add GetFocused to field_input

[SpyMachine]

My use case is that I have a field that I'd like to update suggestions for based on what the user has input. When the user starts typing, a search endpoint is hit with the current value of the field as the query parameter and the suggestions is updated based off the returned search.

So basically, in my Update I want to check if the field is focused and then if a new key was pressed to hit the endpoint and update the suggestions.

[maaslalani]

Hey @SpyMachine, we are going to introduce Dynamic Inputs in #233 which I think will solve your use case here: essentially you'll be able to set the SuggestionsFunc based on the value of the input.

[maaslalani]

Hey @SpyMachine, dynamic inputs are now merged. Let me know if this example is what you were trying to accomplish:

https://github.com/charmbracelet/huh/blob/main/examples/dynamic/dynamic-suggestions/main.go