Use proper doxygen markup to mark deprecations
diff --git a/include/polarssl/cipher.h b/include/polarssl/cipher.h
index 977cc97..6773f61 100644
--- a/include/polarssl/cipher.h
+++ b/include/polarssl/cipher.h
@@ -376,7 +376,7 @@
  * \brief               Free the cipher-specific context of ctx. Freeing ctx
  *                      itself remains the responsibility of the caller.
  *
- * \note                Deprecated: Redirects to cipher_free()
+ * \deprecated          Use cipher_free() instead
  *
  * \param ctx           Free the cipher-specific context
  *