The top-level xsd:annotation
element describes the schema
Its xsd:documentation
child element describes the schema
for human readers
Its xsd:appInfo
child element describes the schema
for computer programs; e.g. stylesheet instructions
<xsd:annotation>
<xsd:documentation>
Song schema for XML and Java Example at XML One
Copyright 2000 Elliotte Rusty Harold.
</xsd:documentation>
</xsd:annotation>