[Bug-gsl] A couple typos

[pfifo fast]

I found a few typos,

Section 18.4 
http://www.gnu.org/s/gsl/manual/html_node/Sampling-from-a-random-number-generator.html

I think the word 'be' is missing here:
The values of min and max can determined using the auxiliary functions
gsl_rng_max (r) and gsl_rng_min (r).

And I think the author wanted a closing square bracket here:
This function returns a double precision floating point number
uniformly distributed in the range [0,1).