Mention psa_close_key in the description of psa_open_key
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 22dea8f..fc5d807 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -543,6 +543,8 @@
*
* Open a handle to a key which was previously created with
* psa_make_key_persistent() when setting its attributes.
+ * The handle should eventually be closed with psa_close_key()
+ * to release associated resources.
*
* Implementations may provide additional keys that can be opened with
* psa_open_key(). Such keys have a key identifier in the vendor range,