## Description 

- Added warning suppression via an `#[allow(..)]` attribute
- Warnings now tell you how to suppress them 
- Special ones include `allow(unused)` and `allow(all)` to suppress
unused item warnings or any warning respectively
  - Thoughts on surfacing these in the help message?

## Test Plan 

- Added tests

---
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### Type of Change (Check all that apply)

- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes