Trailing comma in params causes failure

[bradycharron]

With PHP 7.3 we can now add trailing commas to multiline function definitions. However, doing so causes the following error:

Command 'Insert PHP Docblock' resulted in an error (Running the contributed command: 'php-docblocker.trigger' failed.)

Here is an example function that causes the error.

public function withTrailingParamComma(
    string $trailingComma,
): string {
    return '';
}