Minor improvements in bignum documentation
diff --git a/include/mbedtls/bignum.h b/include/mbedtls/bignum.h
index d3337d2..7b80838 100644
--- a/include/mbedtls/bignum.h
+++ b/include/mbedtls/bignum.h
@@ -688,9 +688,11 @@
* A = Q * B + R
*
* \param Q The destination MPI for the quotient.
- * May be \c NULL is the value of the quotient is not needed.
+ * This may be \c NULL if the value of the
+ * quotient is not needed.
* \param R The destination MPI for the remainder value.
- * May be \c NULL if the value of the remainder is not needed.
+ * This may be \c NULL if the value of the
+ * remainder is not needed.
* \param A The divident. This must point to an initialized MPi.
* \param B The divisor. This must point to an initialized MPI.
*
@@ -707,9 +709,11 @@
* A = Q * b + R
*
* \param Q The destination MPI for the quotient.
- * May be \c NULL is the value of the quotient is not needed.
+ * This may be \c NULL if the value of the
+ * quotient is not needed.
* \param R The destination MPI for the remainder value.
- * May be \c NULL if the value of the remainder is not needed.
+ * This may be \c NULL if the value of the
+ * remainder is not needed.
* \param A The divident. This must point to an initialized MPi.
* \param b The divisor.
*
@@ -922,7 +926,7 @@
* \param X The destination MPI to store the generated prime in.
* This must point to an initialized MPi.
* \param nbits The required size of the destination MPI in bits.
- * Must be between \c 3 and #MBEDTLS_MPI_MAX_BITS.
+ * This must be between \c 3 and #MBEDTLS_MPI_MAX_BITS.
* \param flags A mask of flags of type #mbedtls_mpi_gen_prime_flag_t.
* \param f_rng The RNG function to use. This must not be \c NULL.
* \param p_rng The RNG parameter to be passed to \p f_rng.