I don't think removing the documentation for a deprecated item is a good solution.  If people find it somewhere (old code, googling, via dir()) and find no related documentation, they might keep using it.
If it's clearly documented that the item exists but it's deprecated, people will avoid it (or at least be aware of what it does and the reason why it's deprecated).

I think it would be better to add back the documentation with a deprecated-removed directive, and possibly add warnings in the code (if they are not there already).  In future versions we can remove code and docs together.