Clarify language about restrictions inside the References to Inner Elements section

[sichvoge]

Currently the spec states:

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There are only a few restrictions:

• Validation of any XML or JSON instance against inner elements follows the same restrictions as the validation against a regular XML or JSON schema.
• Referencing complex types inside an XSD is valid to determine the structure of an XML instance, but since complex types do not define a name for the top-level XML element, these types cannot be used for serializing an XML instance.

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The first restriction below hardly seems like a restriction, so I'm not sure what is the point here. The second bullet point also does not seem like a restriction, more like an observation. It would be good to find a different way to explain that.