[drupal-docs] cron jobs in the install text

[Gabor Hojtsy]

> [cron stuff]
> 
>> IN the install text?
> 
> [...]
> 
>> How essential is this to drupal working?
> 
>     [In 4.5.2], search.module won't build an index without it, thus 
> searches  return no results.  Any module can implement a cron hook, too, 
> so it could  potentially cause problems with every module.
> 
>     In other words, fairly essential. :)

And several temporary database stored stuff will not get flushed, and 
your database will get very big soon, with caches, watchdog messages, etc.

Goba