## Description 

- `balance::create_staking_rewards` and
`balance::destroy_storage_rebates` are private functions used by
validators to deal with SUI staking rewards and storage rebates.
- This change is nonfunctional, but should make it more clear within
Move to understand their usage

## Test plan 

- Run tests

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## Release notes

Check each box that your changes affect. If none of the boxes relate to
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that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:
- [ ] REST API: