Detect unused local variables (including in Yul blocks)

### What bug did Slither miss and which detector did you anticipate would catch it?

1. Clone the optimism [repo](https://github.com/ethereum-optimism/optimism/) and `cd packages/contracts-bedrock`.
2. Open `L1Block.sol` and in `setL1BlockValuesEcotone`, notice the unused `let data := calldataload(4)`.
3. Update the `slither.config.json` so no checks are excluded.
4. Run `slither .` (side error: running `slither ./src/L2/L1Block.sol` gives a compilation error that I haven't looked into yet), which does not find the unused `data` variable.

### Frequency

Not sure

### Code example to reproduce the issue:

See above

### Version:

0.10.0

### Relevant log output:

_No response_