extensions/typescript-language-features/src/languageFeatures/callHierarchy.ts/isSourceFileItem
function isSourceFileItem(item: Proto.CallHierarchyItem) {
	return item.kind === PConst.Kind.script || item.kind === PConst.Kind.module && item.selectionSpan.start.line === 1 && item.selectionSpan.start.offset === 1;
}