[Content]: Missing description of the `mixed` setting for Kinesis Firehose

[bockets]

What article on segment.com/docs is affected?

https://segment.com/docs/connections/destinations/catalog/amazon-kinesis-firehose/#settings

What part(s) of the article would you like to see updated?

Under the Settings section, there's a table for configuration options.

The first body row in the table, last cell, starts with:

mixed, defaults to .

It's unclear what this is referencing.

Additional information

No response

[github-actions]

This issue is stale because it has been open 60 days with no activity.