Documentations: correct net_cachelines title for struct inet_sock

The fast path usage breakdown describes the detail for 'inet_sock', fix
the markup title.
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/net_cachelines/inet_sock.rst

 .. SPDX-License-Identifier: GPL-2.0
 .. Copyright (C) 2023 Google LLC
 
-=====================================================
-inet_connection_sock struct fast path usage breakdown
-=====================================================
+==========================================
+inet_sock struct fast path usage breakdown
+==========================================
 
 Type                    Name                  fastpath_tx_access  fastpath_rx_access  comment
 ..struct                ..inet_sock