parseAbi fails when the human readable ABI contains a `fallback()` function

[joaquim-verges]

Describe the bug

Works fine with receive(), but fallback() throws an error. See steps to reproduce below.

Link to Minimal Reproducible Example

No response

Steps To Reproduce

    const abi = formatAbi([
      {
        stateMutability: "payable",
        type: "fallback",
        inputs: [],
        outputs: [],
      },
    ]);
    const abi2 = parseAbi(abi);
    // throws
    // UnknownSignatureError: Unknown signature.
    // Details: fallback()
    // Version: abitype@1.0.5

Package Version

1.0.5

TypeScript Version

5.0.4

Check existing issues

• [X] I checked there isn't already an issue for the bug I encountered.

Anything else?

No response

[Raiden1411]

This was changed in #229 but the format function change wasn't made to accommodate to those changes. See here.

You can create a PR with these changes if you want.