* Add missing versionadded strings for v1.3
* Add missing versionchanged string for Message.edit
* Consistently use versionadded for attributes
* Consistently use versionchanged for parameters
* Use versionchanged for Bot.is_owner
* Fix references in v1.3 changelog
* Improve grammar in v1.3 changelog
The Asset PR (be227ebcf0c8bad6b56798339b5414b8da414dc0) changed some namedtuple-deriving
classes to object-deriving classes, which meant that the free __repr__ provided by namedtuple
was removed
Most assets now return a new class named `Asset`. This allows for the
assets to be consistently saved via a `save` method instead of special
casing for `Attachment`.
`AppInfo` is no longer a namedtuple it is a fully documented dataclass,
as well as having the state attached to it.
Fixes#1997
