[patch, gas documentation] Describe handling of opcodes for relaxation a bit better

[Nick Clifton]

Hi Thomas,

> here's a patch for the documentation that I wish had been in there
> before I started looking at this :-) I've also left in the original
> advice, although that is much more complex than what I found in
> the ports mentioned in the patch.

Thanks very much.  I have applied your patch to the sources.

Cheers
   Nick