* Chain-selection subsystem data revert

* Cargo fmt

* Better code comments

* Remove unwraps

* Document public method

* Remove duplicated 'ChainSelectionSubsystem' impl block

* Fix typos

* Nitpicks

* Revert returns a service Error

* Removed superflous error handling

* Apply suggestions from code review

* Rename tree 'revert' to 'revert_to'

Co-authored-by: Sebastian Kunert <[email protected]>