Spring SimpleMethodMetadataReadingVisitor.Source.toString() omits separator for method arguments

The toString() implementation in SimpleMethodMetadataReadingVisitor.Source does not separate method argument types with a comma.

For example, it generates org.example.MyClass.myMethod(java.lang.Stringjava.lang.Integer) instead of org.example.MyClass.myMethod(java.lang.String,java.lang.Integer).