private void insertArg(FunctionDefinition funcDef, int index, String argName, DataType argDT) {
		List<ParameterDefinition> args = new ArrayList<>(Arrays.asList(funcDef.getArguments()));
		args.add(index, new ParameterDefinitionImpl(argName, argDT, null));
		funcDef.setArguments(args.toArray(ParameterDefinition[]::new));
	}
Returns function definition information for a func.

@param funcData {@link GoFuncData} representing a go func
@return {@link FuncDefResult} record, or null if no information could be found or
generated
@throws IOException if error reading type info
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/golang/rtti/GoRttiMapper.java