escaping data:image when not required

[8ctopus]

I've noticed that the following CSS gets escaped when it doesn't need to:

$input = <<<CSS
a {
  background-image: url("data:image/svg+xml,%3Csvg width='24' height='24' viewBox='0 0 24 24' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath fill-rule='evenodd' clip-rule='evenodd' d='M14.3145 2 3V11.9987H17.5687L18 8.20761H14.3145L14.32 6.31012C14.32 5.32134 14.4207 4.79153 15.9426 4.79153H17.977V1H14.7223C10.8129 1 9.43687 2.83909 9.43687 5.93187V8.20804H7V11.9991H9.43687V23H14.3145Z' fill='black'/%3E%3C/svg%3E%0A");
}

CSS;

$document = (new \Sabberworm\CSS\Parser($input))
    ->parse();

$format = OutputFormat::createPretty();

echo $document->render($format);

result:

a {
        background-image: url("data:image/svg+xml,%3Csvg width=\'24\' height=\'24\' viewBox=\'0 0 24 24\' fill
=\'none\' xmlns=\'http://www.w3.org/2000/svg\'%3E%3Cpath fill-rule=\'evenodd\' clip-rule=\'evenodd\' d=\'M14.3
145 2 3V11.9987H17.5687L18 8.20761H14.3145L14.32 6.31012C14.32 5.32134 14.4207 4.79153 15.9426 4.79153H17.977V
1H14.7223C10.8129 1 9.43687 2.83909 9.43687 5.93187V8.20804H7V11.9991H9.43687V23H14.3145Z\' fill=\'black\'/%3E
%3C/svg%3E%0A");
}

This happens in the following code:

PHP-CSS-Parser/src/Value/CSSString.php

Lines 91 to 96 in 0ae1fde

	public function render(OutputFormat $outputFormat): string
	{
	$string = \addslashes($this->string);
	$string = \str_replace("\n", '\\A', $string);
	return $outputFormat->getStringQuotingType() . $string . $outputFormat->getStringQuotingType();
	}

Would it be possible to check the quoting type and only escape when actually required?