Remove trusted_third_party_id_servers from new configs (matrix-org#5536)

Signed-off-by: Aaron Raimist <[email protected]>

docs/sample_config.yaml

@@ -1145,24 +1145,6 @@ account_validity:
 #
 #default_identity_server: https://matrix.org
 
-# The list of identity servers trusted to verify third party
-# identifiers by this server.
-#
-# Also defines the ID server which will be called when an account is
-# deactivated (one will be picked arbitrarily).
-#
-# Note: This option is deprecated. Since v0.99.4, Synapse has tracked which identity
-# server a 3PID has been bound to. For 3PIDs bound before then, Synapse runs a
-# background migration script, informing itself that the identity server all of its
-# 3PIDs have been bound to is likely one of the below.
-#
-# As of Synapse v1.4.0, all other functionality of this option has been deprecated, and
-# it is now solely used for the purposes of the background migration script, and can be
-# removed once it has run.
-#trusted_third_party_id_servers:
-#  - matrix.org
-#  - vector.im
-
 # Handle threepid (email/phone etc) registration and password resets through a set of
 # *trusted* identity servers. Note that this allows the configured identity server to
 # reset passwords for accounts!

synapse/config/registration.py

@@ -333,24 +333,6 @@ def generate_config_section(self, generate_secrets=False, **kwargs):
         #
         #default_identity_server: https://matrix.org
 
-        # The list of identity servers trusted to verify third party
-        # identifiers by this server.
-        #
-        # Also defines the ID server which will be called when an account is
-        # deactivated (one will be picked arbitrarily).
-        #
-        # Note: This option is deprecated. Since v0.99.4, Synapse has tracked which identity
-        # server a 3PID has been bound to. For 3PIDs bound before then, Synapse runs a
-        # background migration script, informing itself that the identity server all of its
-        # 3PIDs have been bound to is likely one of the below.
-        #
-        # As of Synapse v1.4.0, all other functionality of this option has been deprecated, and
-        # it is now solely used for the purposes of the background migration script, and can be
-        # removed once it has run.
-        #trusted_third_party_id_servers:
-        #  - matrix.org
-        #  - vector.im
-
         # Handle threepid (email/phone etc) registration and password resets through a set of
         # *trusted* identity servers. Note that this allows the configured identity server to
         # reset passwords for accounts!