I hope to see a Tech Help video on this soon. Thanks for posting!

Is this through an Office or Windows update as I am not seeing this when viewing design view of a query...

It's an Office update (Access 365 only).
You need to go to SQL View, not Design View.

Sure I read you can only write comments at the start of the query and they are stored in their own system table.

You are correct.
The name of the System Table is MSysSQLComments

I just upgraded my 365.

Do you know if something similar going to be available for VBA editor?

It is slow to load. but looks great.

I highly doubt the VBA Editor will be updated.
It's a shared component between all apps and is handled by a different team.
Doesn't it have Syntax Highlighting anyway?

I ran the office updates and I am still not seeing it.  It will most likely happen at some point....

Had to exit Access and then come back in and now I see it...