Adjust the score for the serialization vulnerability

* and some additional clarifications
* and some cleanup of wrong rst format

(cherry picked from commit a79bfbf941e5129fcf21d8a9e29d1ae1c55e39a0)

akka-docs/rst/scala/remoting-artery.rst

@@ -264,7 +264,9 @@ It should be protected by network security, such as a firewall. There is current
 so if network security is not considered as enough protection the classic remoting with
 :ref:`TLS and mutual authentication <remote-tls-scala>`  should be used.
 
-It is also security best-practice to :ref:`disable the Java serializer <disable-java-serializer-java-artery>` because of 
+Best practice is that Akka remoting nodes should only be accessible from the adjacent network.
+
+It is also security best practice to :ref:`disable the Java serializer <disable-java-serializer-java-artery>` because of 
 its multiple `known attack surfaces <https://community.hpe.com/t5/Security-Research/The-perils-of-Java-deserialization/ba-p/6838995>`_.
 
 Untrusted Mode

akka-docs/rst/scala/remoting.rst

@@ -519,6 +519,9 @@ a certificate from the connecting peer. Without this mode only the client side i
 While Akka is a peer-to-peer technology, each connection between nodes starts out from one side (the "client") towards 
 the other (the "server").
 
+Note that if TLS is enabled with mutual authentication there is still a risk that an attacker can gain access to a valid certificate
+by compromising any node with certificates issued by the same internal PKI tree.
+
 See also a description of the settings in the :ref:`remote-configuration-scala` section.
 
 .. note::

akka-docs/rst/scala/stream/stages-overview.rst

@@ -883,7 +883,7 @@ Similar to ``Flow.fromSinkAndSource`` however couples the termination of these t
 E.g. if the emitted ``Flow`` gets a cancellation, the ``Source`` of course is cancelled,
 however the Sink will also be completed. The table below illustrates the effects in detail:
 
-+-------------------------------------------------+-----------------------------+---------------------------------+
++=================================================+=============================+=================================+
 | Returned Flow                                   | Sink (in)                   | Source (out)                    |
 +=================================================+=============================+=================================+
 | cause: upstream (sink-side) receives completion | effect: receives completion | effect: receives cancel         |