elementMatchesName function
Whether element matches name: the wildcard *, its name, or
prefix:name with its namespace prefix.
Port of TreeElementNameComparator.elementMatchesName.
Implementation
bool elementMatchesName(TreeElement element, String name) {
if (name == TreeReference.nameWildcard) return true;
if (element.name == name) return true;
final prefix = element.namespacePrefix;
return prefix != null && '$prefix:${element.name}' == name;
}