Fix documentation

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/include/psa/crypto_builtin_primitives.h b/include/psa/crypto_builtin_primitives.h
index c76bc78..f3e438d 100644
--- a/include/psa/crypto_builtin_primitives.h
+++ b/include/psa/crypto_builtin_primitives.h
@@ -7,10 +7,10 @@
  * \note This file may not be included directly. Applications must
  * include psa/crypto.h.
  *
- * \note This header and its content is not part of the Mbed TLS API and
+ * \note This header and its content are not part of the Mbed TLS API and
  * applications must not depend on it. Its main purpose is to define the
  * multi-part state objects of the Mbed TLS software-based PSA drivers. The
- * definition of these objects are then used by crypto_struct.h to define the
+ * definitions of these objects are then used by crypto_struct.h to define the
  * implementation-defined types of PSA multi-part state objects.
  */
 /*