docs: bridge: add other features

Add some features that are not appropriate for the existing section to
the "Others" part of the bridge document.

Acked-by: Nikolay Aleksandrov <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: Hangbin Liu <[e-mail]>
Signed-off-by: Paolo Abeni <[e-mail]>

Documentation/networking/bridge.rst

···
 ip(6)tables to filter packets forwarded by the bridge, or NAT bridged
 traffic. For pure link layer filtering, this module isn't needed.
 
+Other Features
+==============
+
+The Linux bridge also supports `IEEE 802.11 Proxy ARP
+<https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=958501163ddd6ea22a98f94fa0e7ce6d4734e5c4>`_,
+`Media Redundancy Protocol (MRP)
+<https://lore.kernel.org/netdev/[e-mail]/>`_,
+`Media Redundancy Protocol (MRP) LC mode
+<https://lore.kernel.org/r/[e-mail]>`_,
+`IEEE 802.1X port authentication
+<https://lore.kernel.org/netdev/[e-mail]/>`_,
+and `MAC Authentication Bypass (MAB)
+<https://lore.kernel.org/netdev/[e-mail]/>`_.
+
 FAQ
 ===