[Mecha Munch Management]:  Hints File has Missing Link Ref

<img width="919" alt="Image" src="https://github.com/user-attachments/assets/1317b62e-487f-4b10-b7fa-caa95da68df8" />

Link ref to `dict keys` needs to be added to [hints file](https://github.com/exercism/python/blob/main/exercises/concept/mecha-munch-management/.docs/hints.md)