[docs] fix typo in comment (#8609)
diff --git a/include/openthread/instance.h b/include/openthread/instance.h
index ced184f..c766b40 100644
--- a/include/openthread/instance.h
+++ b/include/openthread/instance.h
@@ -53,7 +53,7 @@
* @note This number versions both OpenThread platform and user APIs.
*
*/
-#define OPENTHREAD_API_VERSION (273)
+#define OPENTHREAD_API_VERSION (274)
/**
* @addtogroup api-instance
diff --git a/include/openthread/platform/crypto.h b/include/openthread/platform/crypto.h
index 9d99819..69253bb 100644
--- a/include/openthread/platform/crypto.h
+++ b/include/openthread/platform/crypto.h
@@ -337,7 +337,7 @@
* Start HMAC operation.
*
* @param[in] aContext Context for HMAC operation.
- * @param[in] aKey Key material to be used for for HMAC operation.
+ * @param[in] aKey Key material to be used for HMAC operation.
*
* @retval OT_ERROR_NONE Successfully started HMAC operation.
* @retval OT_ERROR_FAILED Failed to start HMAC operation.