Update doc/source/nmod_mat.rst

Co-authored-by: Vincent Neiger <vneiger@users.noreply.github.com>

Author: dlesnoff

doc/source/nmod_mat.rst

@@ -201,7 +201,7 @@ Random matrix generation
 
 .. function:: void nmod_mat_randunif(nmod_mat_t mat, flint_rand_t state)
 
-    Sets the element to uniformly generated random numbers between `0` and `m-1`. This is used for benchmarks.
+    Sets the element to uniformly generated random numbers in `[0, n)`, where `n` is the modulus of the matrix.
 
 .. function:: int nmod_mat_randpermdiag(nmod_mat_t mat, flint_rand_t state, nn_srcptr diag, slong n)