Fixed code completion after opening bracket, issue 3977

scene/gui/text_edit.cpp

@@ -3911,6 +3911,9 @@ void TextEdit::_update_completion_candidates() {
 		}
 	}
 
+	if (l[cursor.column - 1] == '(' && !pre_keyword) {
+		cancel = true;
+	}
 
 	update();