Fixes after release

A few documentation related fixes:
https://hibernate.atlassian.net/browse/OGM-582
https://hibernate.atlassian.net/browse/OGM-548
> The method getTargetEntityKeyColumnNames() will return: id

But there is no such method, right?

Regarding your example, wouldn't you obtain `bankAccounts_id` by doing

    rowKeyColumnNames - columnNames - rowKeyIndexColumnNames

as I suggested before:

    [owners_id, bankAccounts_id] - [owners_id] - [] = [bankAccounts_id]

?

There seems to be a case where this doesn't work, but I'm still trying to understand which one it is.