WildTypePattern.toString: do not parenthesesise generic type list

WildTypePattern.toString: do not parenthesesise generic type list

It is unnecessary to represent a pattern list 'A,B,C' as '(A,B,C)'. Not
only does it look ugly in a type signature like 'org.acme.Foo<(A,B,C)>',
but also is it not valid Java syntax. While the latter might not be
strictly necessary in a String representation, it certainly is
desirable, if such representations are ever used to generate code or
@AspectJ pointcut annotations.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>