[RFA][Python] Change gdb.Value.address from a method to an attribute.

[Eli Zaretskii]

> From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> Cc: gdb-patches@sourceware.org
> Date: Sat, 28 Mar 2009 18:18:57 -0300
> 
> +@defmethod Value address
> +If the @code{gdb.Value} object is addressable, this read-only attribute
> +holds a @code{gdb.Value} object representing the address.  Otherwise,
> +this attribute holds @code{None}.
> +@end defmethod

The two uses of `gdb.Value' so close to one another and meaning two
different things might confuse the reader.  Is it really important to
make the point that the address attribute is itself a `gdb.Value'?  If
not, I'd suggest to rephrase:

  If the @code{gdb.Value} object is addressable, this read-only
  attribute holds its address.

Thanks.