Threat Model: Align indentation of Spying Threats.

“Disclosure to Servers Within Chatroom” was indented lesser
than the surrounding threats.

Signed-off-by: Florian Jacob <projects+git AT florianjacob )DOT( de>

specification/appendices/threat_model.rst

@@ -134,7 +134,7 @@ An attacker could try to convince servers within a chatroom to send messages to
 a server it controls that was not authorised to be within the chatroom.
 
 Threat: Disclosure to Servers Within Chatroom
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
++++++++++++++++++++++++++++++++++++++++++++++
 
 An attacker could take control of a server within a chatroom to expose message
 contents or metadata for messages in that room.