Add setting to control DHT nodeslist update frequency

Also rename a few things and semi-fix man page format issues

doc/toxic.1.asc

@@ -41,7 +41,7 @@ OPTIONS
     Show help message
 
 -n, --nodes nodes-file::
-    Use specified 'nodes-file' for DHT bootstrap nodes, instead of the default
+    Use specified 'nodes-file' for DHT bootstrap nodes instead of '~/.config/tox/DHTnodes.json'
 
 -o, --noconnect::
     Do not connect to the DHT network
@@ -69,7 +69,7 @@ FILES
 -----
 ~/.config/tox/DHTnodes.json::
     Default location for list of DHT bootstrap nodes (list obtained from https://nodes.tox.chat).
-    This list is automatically updated every 30 days.
+    This list is automatically updated. See *toxic.conf*(5) for details on controlling the update frequency.
 
 ~/.config/tox/toxic_profile.tox::
     Savestate which contains your personal info (nickname, Tox ID, contacts,