* option to report details of unused snapshots ([467](https://github.com/tophat/syrupy/issues/467)), close [#465](https://github.com/tophat/syrupy/issues/465) ([1c50db0](https://github.com/tophat/syrupy/commit/1c50db0c5aa6f2d7445cc0aa8fd532c48d593f2e))