What are you talking about? Of all the problems PHP has (and there are many), the documentation is not one of them. It (php.net) is complete, easy to browse or use as a reference, mostly accurate and even includes comments where community with good intentions (but admittedly, usually less good knowledge) helps clarify any corner cases. Which you can ignore of course.

The language itself sucks (and this bleeds into the code), but the idea of it and the documentation are great imho.