adjusting comment on sliding window memory usage.
The comment now uses '**' as exponentiation operator.
* Maximum window size used for modular exponentiation. Default: 6
* Minimum value: 1. Maximum value: 6.
*
- * Result is an array of ( 2 << MBEDTLS_MPI_WINDOW_SIZE ) MPIs used
+ * Result is an array of ( 2 ** MBEDTLS_MPI_WINDOW_SIZE ) MPIs used
* for the sliding window calculation. (So 64 by default)
*
* Reduction in size, reduces speed.
