Document defaults (#3863)

* Begin fixing incorrect defaults

* Fix more defaults

* Make more defaults correct

* Update cli-help.txt

(To show what this PR does)

* Lint

* Extend argparse rather than vendoring it

* lint

* Move sample User Agent generation into the same module as UA generation

* Revert cli-help.txt to previous release version

* Slightly more consistent linebreaks

certbot/plugins/manual.py

@@ -98,7 +98,7 @@ s.serve_forever()" """
         add("test-mode", action="store_true",
             help="Test mode. Executes the manual command in subprocess.")
         add("public-ip-logging-ok", action="store_true",
-            help="Automatically allows public IP logging.")
+            help="Automatically allows public IP logging. (default: Ask)")
 
     def prepare(self):  # pylint: disable=missing-docstring,no-self-use
         if self.config.noninteractive_mode and not self.conf("test-mode"):

certbot/plugins/webroot.py

@@ -45,7 +45,7 @@ to serve all files under specified web root ({0})."""
                  "times to handle different domains; each domain will have "
                  "the webroot path that preceded it.  For instance: `-w "
                  "/var/www/example -d example.com -d www.example.com -w "
-                 "/var/www/thing -d thing.net -d m.thing.net`")
+                 "/var/www/thing -d thing.net -d m.thing.net` (default: Ask)")
         add("map", default={}, action=_WebrootMapAction,
             help="JSON dictionary mapping domains to webroot paths; this "
                  "implies -d for each entry. You may need to escape this from "