Section "Instances" - document why quantity of Direct instances can be higher than of All instances

[annainfo]

https://tools.wmflabs.org/sqid/#/view?id=Q5

1) Direct instances | 4240876

2) All instances (Total number of unique instances of this class and its 1009 direct and indirect subclasses) | 4096375

Seems page has some undocumented counting algorithm(s) involved here.

[mkroetzsch]

This is due to the fact that the "all instances" metric is computed offline, and therefore can be outdated. The UI should have a warning, or we should make sure that updates happen more often.

[annainfo]

1) ai: Section "Instances" - Document why quantity of Direct instances is higher than of All instances 2) mk: Section "Instances": number of "all instances" can be outdated 3) ai: Section "Instances" - Document why quantity of Direct instances can be higher than of All instances "outdated" does not address the data inconsistency