Adjust backport's documentation to account for missing features
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index da0c5ca..5fd6969 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -2107,8 +2107,8 @@
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
 /**
  * \brief          Set the maximum fragment length to emit and/or negotiate.
- *                 (Typical: the smaller of #MBEDTLS_SSL_IN_CONTENT_LEN and
- *                 #MBEDTLS_SSL_OUT_CONTENT_LEN, usually `2^14` bytes)
+ *                 (Typical: #MBEDTLS_SSL_MAX_CONTENT_LEN, by default that is
+ *                 set to `2^14` bytes)
  *                 (Server: set maximum fragment length to emit,
  *                 usually negotiated by the client during handshake)
  *                 (Client: set maximum fragment length to emit *and*