Validate MarkupMultiline

[RS-Credentive]

https://github.com/usnistgov/metaschema/blob/develop/schema/xml/metaschema-markup-multiline.xsd

<xs:group name="headingBlockElementGroup">
xs:choice
<xs:element name="h1" type="inlineMarkupType"/>
<xs:element name="h2" type="inlineMarkupType"/>
<xs:element name="h3" type="inlineMarkupType"/>
<xs:element name="h4" type="inlineMarkupType"/>
<xs:element name="h5" type="inlineMarkupType"/>
<xs:element name="h6" type="inlineMarkupType"/>
</xs:choice>
</xs:group>

<xs:group name="blockElementGroup">
xs:choice
<xs:group ref="headingBlockElementGroup"/>
<xs:group ref="listsGroup"/>
<xs:group ref="blockTextGroup"/>
<xs:element name="p" type="inlineMarkupType"/>
<xs:element name="table" type="tableType"/>

<xs:element name="img" type="imageType"/>
</xs:choice>
</xs:group>

<xs:group name="blockTextGroup">
xs:choice
<xs:element name="pre" type="preformattedType"/>
<xs:element name="hr"/>

<xs:element name="blockquote" type="blockQuoteType"/>
</xs:choice>
</xs:group>

<xs:complexType name="preformattedType" mixed="true">
xs:complexContent
<xs:extension base="inlineMarkupType">
xs:annotation
xs:documentationThe content model is the same as inlineMarkupType, but line endings need
to be preserved, since this is pre-formatted.</xs:documentation>
</xs:annotation>
</xs:extension>
</xs:complexContent>
</xs:complexType>

<xs:complexType name="listType">
xs:sequence
<xs:element name="li" type="listItemType" minOccurs="1" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>

<xs:complexType name="orderedListType">
xs:complexContent
<xs:extension base="listType">

<xs:attribute name="start" type="xs:nonNegativeInteger"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>

<xs:group name="listsGroup">
xs:choice
<xs:element name="ul" type="listType"/>
<xs:element name="ol" type="orderedListType"/>
</xs:choice>
</xs:group>

<xs:complexType name="listItemType" mixed="true">

<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:group ref="inlineMarkupGroup"/>
<xs:group ref="listsGroup"/>
<xs:group ref="blockTextGroup"/>
<xs:group ref="headingBlockElementGroup"/>
<xs:element name="p" type="inlineMarkupType"/>
</xs:choice>
</xs:complexType>

<xs:complexType name="tableType">
xs:sequence
<xs:element maxOccurs="unbounded" name="tr" type="tableRowType"/>
</xs:sequence>
</xs:complexType>

<xs:complexType name="tableRowType">

<xs:choice minOccurs="1" maxOccurs="unbounded">
<xs:element name="td" type="tableCellType" maxOccurs="unbounded"/>
<xs:element name="th" type="tableCellType" maxOccurs="unbounded"/>
</xs:choice>
</xs:complexType>

<xs:complexType name="tableCellType" mixed="true">
xs:complexContent

<xs:extension base="inlineMarkupType">

<xs:attribute name="align" type="alignType" default="left"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>

<xs:simpleType name="alignType">
<xs:restriction base="xs:token">
<xs:enumeration value="left"/>
<xs:enumeration value="center"/>
<xs:enumeration value="right"/>
</xs:restriction>
</xs:simpleType>

<xs:complexType name="blockQuoteType">

<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:group ref="blockElementGroup"/>
</xs:choice>
</xs:complexType>