Support function types in ParamType

[mattsse]

The ParamType currently does not support Function types.

a function type

 function map(uint[] memory self, function (uint) pure returns (uint) f)

get's type

"abi": [
	{
	"inputs": [
		{
			"internalType": "uint256[]",
			"name": "self",
			"type": "uint256[]"
		},
		{
			"internalType": "function (uint256) pure external returns (uint256)",
			"name": "f",
			"type": "function"
		}
	],
	"name": "map",
	"outputs": [],
	"stateMutability": "nonpayable",
	"type": "function"
	}
]

the methodIdentifier would be

"map(uint256[],function)": "8bd968ff"

"type": "function" is currently only supported on Contract level and not for, this could be achieved by adding a ParamType::Function variant