Update torrc to encourage use of BridgeDistribution

Bridge operators should generally publish their descriptors except for
rare cases, and instead use the BridgeDistribution none setting to
prevent their bridge from being distributed by BridgeDB.

src/config/torrc.minimal.in-staging

@@ -224,4 +224,4 @@
 ## mechanisms like https://bridges.torproject.org/. If you want to run
 ## a private bridge, for example because you'll give out your bridge
 ## address manually to your friends, uncomment this line:
-#PublishServerDescriptor 0
+#BridgeDistribution none

src/config/torrc.sample.in

@@ -239,7 +239,7 @@
 ## mechanisms like https://bridges.torproject.org/. If you want to run
 ## a private bridge, for example because you'll give out your bridge
 ## address manually to your friends, uncomment this line:
-#PublishServerDescriptor 0
+#BridgeDistribution none
 
 ## Configuration options can be imported from files or folders using the %include
 ## option with the value being a path. This path can have wildcards. Wildcards are