`gas-indexed-events` not working for Interfaces

[0xCLARITY]

PoC:

1. Clone repo: https://github.com/0xCLARITY/solhint-testing
2. Run yarn lint
3. Observe "errors":

yarn lint
yarn run v1.22.21
$ solhint 'src/**/*.sol'

src/ICounter.sol
  4:3  warning  GC: [sender] on Event [Increment] could be Indexed  gas-indexed-events
  4:3  warning  GC: [value] on Event [Increment] could be Indexed   gas-indexed-events

✖ 2 problems (0 errors, 2 warnings)

✨  Done in 0.85s.

4. Look at code:

pragma solidity ^0.8.20;

interface ICounter {
  event Increment (address indexed sender, uint256 indexed value);
}

5. Be confused about alleged warnings.