median: add comment in test median

Author: jvdp1

src/tests/stats/test_median.fypp

@@ -22,6 +22,7 @@ subroutine test_median_${k1}$()
     ${t1}$, allocatable :: d0(:), d1(:), d2(:,:), d3(:,:,:)
 
     allocate(d0(0))
+    !check just to be sure that the setup of d0 is correct
     call check(size(d0) == 0, 'test_median_${k1}$: should be of size 0')
 
     d1 = [10, 2, -3, -4, 6, -6, 7, -8, 9, 0, 1, 20]
@@ -109,6 +110,7 @@ subroutine test_median_${k1}$()
     ${t1}$, allocatable :: d0(:), d1(:), d2(:,:), d3(:,:,:)
 
     allocate(d0(0))
+    !check just to be sure that the setup of d0 is correct
     call check(size(d0) == 0, 'test_median_${k1}$: should be of size 0')
 
     d1 = [10., 2., -3., -4., 6., -6., 7., -8., 9., 0., 1., 20.]