[drupal-docs] Why we decided to add reference to the drupal handbook in administration help

[Angie Byron]

> Well, numerically it might be small, but if you look at the developer
> list, which is full of people, who do ship customized versions of Drupal
> to their customers, then the tempting thought to talk about this
> possibility is big enough to just not let it pass :)

Ok, how about adding a handbook page somewhere (sub-page of the help module 
page?) that describes how to remove the link for developers who don't want this 
(basically would just be a find/replace in files job, since the line will be 
identical across modules). But leave it on by default.

This way if I want to hugely modify my forum code, or I want to sell Drupal as 
SuperCMS 2.0, I will be able to remove that line, but for 99% of everyone else 
it stays there as a helpful pointer to further info.

Deal? ;)

-Angie