MINOR: Re-apply 2.6 docs commit (#275) (4c19eab) (#301)

The PR to make several Streams-relevant changes for the
2.6 release (4c19eab / #275) was accidentally reverted by
35d3b804b86c249aace9a729c5abd9be4525ef3d

This commit restores the desired docs changes.

Reviewers: John Roesler <vvcephei@apache.org>
5 files changed