Revert "Mark CompletionList as complete (microsoft#169574)" (microsoft#172581)

This reverts commit 3834785.

Author: rzhao271

extensions/emmet/src/defaultCompletionProvider.ts

@@ -214,7 +214,7 @@ export class DefaultCompletionItemProvider implements vscode.CompletionItemProvi
 				});
 			}
 
-			return new vscode.CompletionList(newItems);
+			return new vscode.CompletionList(newItems, true);
 		});
 	}
 }