Bug in documetation for gsl_ran_dir_nd

[Brian Gough]

Gavin Crooks writes:
 >  Bug in documetation for gsl_ran_dir_nd In randdist.texi
 >  gsl_ran_dir_nd is documented to take an integer
 > argument,
 >   @deftypefn Random void gsl_ran_dir_nd (const gsl_rng * @var{r},
 >   int
 > @var{n},
 >     double *@var{x})
 >  but in gsl_randist.h is declarted to take size_t.
 > > void gsl_ran_dir_nd (const gsl_rng * r, size_t n, double * x);

Thanks, I'll update the documentation.