URL fixes if using unix_socket

- according to https://github.com/ansible/ansible/pull/43560 where
  unix_socket was implemented, you're supposed to use http://localhost/
  as hostname when using unix_socket

collection/plugins/modules/device.py

@@ -97,7 +97,7 @@ else:
 
 def make_headers(host, api_key, unix_socket=None, device=None):
     url = '{}{}{}{}'.format(
-                            host if not unix_socket else "",
+                            host,
                             SYNCTHING_API_URI,
                             '/' if device else '',
                             device if device else '')