DialogXML: Support <key> in <text> with optional ref=

rsrc/dialogs/cast-spell.xml

@@ -79,10 +79,14 @@
 	<text size='large' top='60' left='209' width='223' height='16'>Target:  HP:   SP:    Status:</text>
 	<text top='0' left='202' width='290' height='57'>
 		Keyboard:
-		Type '1'-'6' to pick caster,
-		Shift-'1' - '6' to select target,
-		'space' for Other Spells,
-		key by spell to cast spell.
+		<key ref='caster1'/><key ref='caster2'/><key ref='caster3'/>
+		<key ref='caster4'/><key ref='caster5'/><key ref='caster6'/>
+		 to pick caster,<br/>
+		<key ref='target1'/><key ref='target2'/><key ref='target3'/>
+		<key ref='target4'/><key ref='target5'/><key ref='target6'/>
+		 to select target,<br/>
+		<key ref='other'/> for Other Spells,<br/>
+		key by spell to cast spell.<br/>
 		Alt-click spell name for description.
 	</text>
 	<button name='help' type='help' def-key='help' top='6' left='596'/>

rsrc/schemas/dialog.xsd

@@ -149,11 +149,16 @@
 		</xs:simpleContent>
 	</xs:complexType>
 	<xs:complexType mixed="true" name="message">
-		<xs:sequence>
-			<xs:element name="br" minOccurs="0" maxOccurs="unbounded">
+		<xs:choice minOccurs="0" maxOccurs="unbounded">
+			<xs:element name="br">
 				<xs:complexType/>
 			</xs:element>
-		</xs:sequence>
+			<xs:element name="key">
+				<xs:complexType>
+					<xs:attribute name='ref' type='xs:token'/>
+				</xs:complexType>
+			</xs:element>
+		</xs:choice>
 		<xs:attribute name="name" type="xs:token"/>
 		<xs:attributeGroup ref="frame"/>
 		<xs:attributeGroup ref="font"/>
@@ -312,5 +317,9 @@
 			<xs:selector xpath="*"/>
 			<xs:field xpath="@anchor"/>
 		</xs:keyref>
+		<xs:keyref name="keyRef" refer="uniqueID">
+			<xs:selector xpath="key"/>
+			<xs:field xpath="@ref"/>
+		</xs:keyref>
 	</xs:element>
 </xs:schema>