nixos/firefox-syncserver: fix and update the docs and options descriptions

nixos/modules/services/networking/firefox-syncserver.md

···
 accessed. The `url` can be configured automatically when using nginx.
 
 Options that affect the surroundings of the sync server are `enableNginx`,
-`enableTLS` and `hostnam`. If `enableNginx` is set the sync server module will
+`enableTLS` and `hostname`. If `enableNginx` is set the sync server module will
 automatically add an nginx virtual host to the system using `hostname` as the
 domain and set `url` accordingly. If `enableTLS` is set the module will also
 enable ACME certificates on the new virtual host and force all connections to

nixos/modules/services/networking/firefox-syncserver.nix

···
           Settings for the sync server. These take priority over values computed
           from NixOS options.
 
-          See the doc comments on the `Settings` structs in
-          <https://github.com/mozilla-services/syncstorage-rs/blob/master/syncstorage/src/settings.rs>
+          See the example config in
+          <https://github.com/mozilla-services/syncstorage-rs/blob/master/config/local.example.toml>
+          and the doc comments on the `Settings` structs in
+          <https://github.com/mozilla-services/syncstorage-rs/blob/master/syncstorage-settings/src/lib.rs>
           and
-          <https://github.com/mozilla-services/syncstorage-rs/blob/master/syncstorage/src/tokenserver/settings.rs>
+          <https://github.com/mozilla-services/syncstorage-rs/blob/master/tokenserver-settings/src/lib.rs>
           for available options.
         '';
       };