addTextStyle method
Add a textstyle
as symbolizer to the rule xml element.
Implementation
void addTextStyle(TextStyle style) {
var textFragment = makeTextStyleBuildFragment(style);
ruleXmlElement.children.add(textFragment);
var tSym = TextSymbolizer(textFragment.children.first as xml.XmlElement);
textSymbolizers.add(tSym);
}