Merge pull request microsoft#185431 from weartist/fix_call_hierarchy_tooltip

Fix microsoft#185051

Author: jrieken

extensions/references-view/src/calls/model.ts

@@ -177,7 +177,7 @@ class CallItemDataProvider implements vscode.TreeDataProvider<CallItem> {
 
 		const item = new vscode.TreeItem(element.item.name);
 		item.description = element.item.detail;
-		item.tooltip = item.label ? `${item.label} - ${element.item.detail}` : element.item.detail;
+		item.tooltip = item.label && element.item.detail ? `${item.label} - ${element.item.detail}` : item.label ? `${item.label}` : element.item.detail;
 		item.contextValue = 'call-item';
 		item.iconPath = getThemeIcon(element.item.kind);