Grammar fix
diff --git a/include/psa/crypto_sizes.h b/include/psa/crypto_sizes.h
index 11c73a9..d7eb482 100644
--- a/include/psa/crypto_sizes.h
+++ b/include/psa/crypto_sizes.h
@@ -447,7 +447,7 @@
* psa_asymmetric_sign() will not fail with
* #PSA_ERROR_BUFFER_TOO_SMALL.
* If the parameters are a valid combination that is not supported
- * by the implementation, this macro either shall return either a
+ * by the implementation, this macro shall return either a
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.
@@ -478,7 +478,7 @@
* psa_asymmetric_encrypt() will not fail with
* #PSA_ERROR_BUFFER_TOO_SMALL.
* If the parameters are a valid combination that is not supported
- * by the implementation, this macro either shall return either a
+ * by the implementation, this macro shall return either a
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.
@@ -509,7 +509,7 @@
* psa_asymmetric_decrypt() will not fail with
* #PSA_ERROR_BUFFER_TOO_SMALL.
* If the parameters are a valid combination that is not supported
- * by the implementation, this macro either shall return either a
+ * by the implementation, this macro shall return either a
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.
@@ -680,7 +680,7 @@
* psa_asymmetric_sign() will not fail with
* #PSA_ERROR_BUFFER_TOO_SMALL.
* If the parameters are a valid combination that is not supported
- * by the implementation, this macro either shall return either a
+ * by the implementation, this macro shall return either a
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.