* Remove deprecated api_spec.yaml
* add prototype for proposer slashing
* remove clippy warnings
* Add proposer_slashing API
* Prototype for attester slashing API call
* Fix logic error in operation pool
* Finish test for attester_slashing api call
* Clean proposer_slashing test
* Cargo fmt
* Remove useless to_string after format! macro
* Cargo fmt
* Update book with new api calls
* Re-enable proposer slashing verification
* Update book with appropriate test example
* Fix proposer_slashing test
* Update comments and tests for clearer code
* Remove extraneous comments
* Fix test
* Minor fix
* Address reviewer comments
Co-authored-by: pscott <30843220+pscott@users.noreply.github.com>