Fix typo in doc and copy missing warning
diff --git a/include/mbedtls/blowfish.h b/include/mbedtls/blowfish.h
index fb16782..985faa4 100644
--- a/include/mbedtls/blowfish.h
+++ b/include/mbedtls/blowfish.h
@@ -211,6 +211,10 @@
* Note that for both stategies, sizes are measured in blocks and
* that a Blowfish block is 8 bytes.
*
+ * \warning Upon return, \p stream_block contains sensitive data. Its
+ * content must not be written to insecure storage and should be
+ * securely discarded as soon as it's no longer needed.
+ *
* \param ctx Blowfish context
* \param length The length of the data
* \param nc_off The offset in the current stream_block (for resuming