Document that bit_reversal_permutation does not work for n==1 (#224)

src/c_kzg_4844.c

@@ -590,11 +590,12 @@ static uint32_t reverse_bits(uint32_t n) {
  * @param[in,out] values The array, which is re-ordered in-place
  * @param[in]     size   The size in bytes of an element of the array
  * @param[in]     n      The length of the array, must be a power of two
- *                       less that 2^32
+ *                       strictly greater than 1 and less than 2^32.
  */
 static C_KZG_RET bit_reversal_permutation(
     void *values, size_t size, uint64_t n
 ) {
+    CHECK(n != 0);
     CHECK(n >> 32 == 0);
     CHECK(is_power_of_two(n));
     CHECK(log2_pow2(n) != 0);