update docs

docs/readme.en.md

@@ -306,7 +306,7 @@ Fakes are separate generated by nfqws packets carrying false information for DPI
 * **datanoack** sends tcp fakes without ACK flag. Servers do not accept this but DPI may accept.
   This mode may break NAT and may not work with iptables if masquerade is used, even from the router itself.
   Works with nftables properly. Likely requires external IP address (some ISPs pass these packets through their NAT).
-* Manipulate tcp flags with `--dpi-desync-tcp-flags-set` and `--dpi-desync-tcp-flags-unset`.
+* Manipulate **tcp flags** with `--dpi-desync-tcp-flags-set` and `--dpi-desync-tcp-flags-unset`.
   Invalid tcp flags combination may cause server to drop the packet but DPI can accept it.
   For example, set SYN in fakes. This may not work with all servers.
   `datanoack` can be replaced to `--dpi-desync-tcp-flags-unset=ACK`.