Update documentation for the Q1 2021 small features release.

[leafpetersen]

This tracks any documentation updates required for this feature set.

cc @kwalrath @franklinyow

[leafpetersen]

@kwalrath any updates?

[leafpetersen]

@kwalrath Any concerns about this being ready for stable?

[kwalrath]

@kwalrath Any concerns about this being ready for stable?

No, no concerns.

[franklinyow]

Any update on this?

[franklinyow]

Synced with @kwalrath, moving to a later milestone