CHANGELOG: fix typo — heartwood

The command that changed is rad node debug, not rad debug.

 - The `Connected` state of a peer no longer contains fetching information. This
   information was returned when requesting for `Seeds` on the control socket.
   Callers should no longer expect the `fetching` inside that JSON result.
 - The `rad debug` information for ongoing fetches contained the number of
 - The `rad node debug` information for ongoing fetches contained the number of
   subscribers awaiting for results, this was removed.
 - The `TypeName` strings defined in `radicle-cob` are restricted to reflect the
   size limits on domain names as specified in