Suggested correction to https://www.w3.org/TR/activitypub/

Hi!

1. I noticed an inaccuracy in section 6.9. "Undo Activity"

"The undo activity and the activity being undone must both have the same
*author*."

"author" should be changed to "actor" here so it will read:

"The undo activity and the activity being undone must both have the same
*actor*."

2. Actually, the "*author*" property is used (informally ?!) in examples of
this document, but I didn't find _any_ reference to such a "property" in
https://www.w3.org/TR/activitystreams-vocabulary/
the latter documents uses "actor" instead.

Looks like autor should be replaced with "*actor*" in examples also to
avoid confusion and incompatible implementations...
?!

-- 
Yuri Volkov