RFA: document raw/virtual stuff

[Jim Blandy]

> > + @section Using Different Register and Memory Data Representations
> > + 
> > + Some architectures use one representation for a value when it lives in a
> > + register, but use a different representation when it lives in memory.
> > + In GDB's terminology, the @dfn{raw} representation is the one used in
> > + the target registers, and the @dfn{virtual} representation is the one
> > + used in memory, and within GDB @code{struct value} objects.
> 
> I suggest these index entries for the above paragraph:
> 
>   @cindex raw representation
>   @cindex virtual representation
>   @cindex @code{struct value}, raw and virtual representation

How about:

@cindex raw representation
@cindex virtual representation
@cindex representations, raw and virtual
@cindex register data formats, converting
@cindex @code{struct value}, converting register contents to