Documentation for TQRootBean.findSingleAttribute incorrect

[J3173]

The method findSingleAttribute of TQRootBean returns either a single value or null when no rows match.

However the JavaDoc documentation states https://github.com/ebean-orm/ebean/blob/4cc012b974455e6deea320273e0c483ddc1b28b1/ebean-querybean/src/main/java/io/ebean/typequery/TQRootBean.java#L1782 which I think is incorrect.

Also the method should be annotated with the @Nullable annotation as it might return a null value. All methods in this class are currently marked as NonNull by default because of the https://github.com/ebean-orm/ebean/blob/4cc012b974455e6deea320273e0c483ddc1b28b1/ebean-querybean/src/main/java/io/ebean/typequery/TQRootBean.java#L61 annotation. This confuses IntelliJ as it thinks findSingleAttribute cannot return a null value.