bug#56251: Make obsoletion info more prominent in *Help* buffer

[Drew Adams]

> > However, I find that the obsoletion warning is
> > easy to miss.  Presumably, this is very important information before
> > even considering using the variable.  We want to strongly discourage
> > that, right?
> >
> > So how about making that particular part more prominent, for example
> > by moving it back up to the top again, or by giving it some color?
> 
> I think moving it back to the top makes sense -- it's very important
> information.

No, it's not more important than the other
meta-information that you've moved to the end.
It's a footnote - should be, anyway.