Rollups 1.5 section on InputAdded event refers to `inboxInputIndex` when the actual ABI is `inputIndex`

[miltonjonat]

Refs:

• Docs page: https://docs.cartesi.io/cartesi-rollups/1.5/rollups-apis/json-rpc/input-box/#inputadded
• Actual code: https://github.com/cartesi/rollups-contracts/blob/v1.4.0/onchain/rollups/contracts/inputs/IInputBox.sol#L14