[Field formatters] provide guidance to user on bit formatting

[drewdaemon]

Describe the feature:
Right now, the way you specify a bit field format is by selecting bytes and creating a numeral.js pattern that specifies that what you really want is bits.

Could we make this more clear by providing some copy around the input or some inline documentation?

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[drewdaemon]

cc @dej611 @stratoula for visibility

[kertal]

Maybe there could be a section to provide helpful examples? I assume you were working on something, could you care what was your use case? An actual example is always helpful, thx!

[drewdaemon]

@kertal due to some requests around bit formatting on the Lens metric, we were evaluating adding a bit field formatter. We decided that wasn't high priority since you can already use the bytes formatter with a custom numeral.js format pattern.

However, it seemed like this workaround wasn't very clear from our UI (i.e. the user might look for a bits field formatter in the list). That's why we created this issue.

[kertal]

Maybe we should relabel it into something like Bits & Bytes

[drewdaemon]

Maybe we should relabel it into something like Bits & Bytes

Not a bad idea.

[ghudgins]

I would suggest Bytes and Bits just so it's easier to find for returning user who is used to Bytes that we have today. can we go with this solution? @l-suarez any objections from the design side?