Allow multiple lines in excludeIf expression annotation

[ixarlie]

I have some issues when I use the excludeIf option with a large expression in the annotation.
I want to split it to see the entire expression without scrolling horizontally.

Example

/**
 * @Hateoas\Relation(
 *     name="foo"
 *     embedded=@Hateoas\Embedded(
 *         "expr(object.getA().getB().getC().getD()",
 *         exclusion=@Hateoas\Exclusion(
 *             groups={"public"},
 *             excludeIf="expr(not object.getA()
   or not object.getA().getB()
   or not object.getA().getB().getC())"
 *         )
 *     )
 * )
 */
class Group

The CheckExpressionTrait::checkExpression method gets the expression like this expr(not object.getA()\n or not object.getA().getB()\n or not object.getA().getB().getC()).

The Symfony Expression Language component will replace all the \n with whitespaces, but the regular expression is not taking the entire expression.

https://github.com/willdurand/Hateoas/blob/master/src/Configuration/Metadata/Driver/CheckExpressionTrait.php#L25

if (is_string($exp) && preg_match('/expr\((?P<expression>.+)\)/', $exp, $matches)) {

So the matching in the expression group is not object.getA(

I am not sure if the regular expression can be updated to use "single line" flag, /expr\((?P<expression>.+)\)/s, so dots matches newline.

Thanks