useMergedRef not being exported by index

[bpas247]

Probably just a missed step in #9, but we should export the useMergedRef hook from src/index.ts.

[Shadowlauch]

The FocusManager is also not reexported

[taion]

Actually, a ton of stuff isn't. Should they be?

[jquense]

probably, but i don't think about it since we cherry-pick

[taion]

Should we get rid of index then?

[Shadowlauch]

Getting rid of the index would introduce a breaking change though. I personally quite like the named exports from an index and with proper tree shaking it does not introduce unnessecary code.