Fix a TypeError in aiocoap-rd

[LP-HAW]

A GET request to /reg/1/ of aiocoap-rd causes a TypeError:

ERROR:coap-server:An exception occurred while rendering a resource: TypeError('link_format_from_message() takes 1 positional argument but 2 were given')
Traceback (most recent call last):
  File "/home/LP-HAW/.local/lib/python3.10/site-packages/aiocoap/protocol.py", line 393, in _render_to_plumbing_request
    await self._render_to_plumbing_request_inner(plumbing_request,
  File "/home/LP-HAW/.local/lib/python3.10/site-packages/aiocoap/protocol.py", line 522, in _render_to_plumbing_request_inner
    response = await self.serversite.render(request)
  File "/home/LP-HAW/.local/lib/python3.10/site-packages/aiocoap/cli/rd.py", line 664, in render
    return await Site.render(self, request)
  File "/home/LP-HAW/.local/lib/python3.10/site-packages/aiocoap/resource.py", line 369, in render
    return await child.render(subrequest)
  File "/home/LP-HAW/.local/lib/python3.10/site-packages/aiocoap/cli/rd.py", line 444, in render
    return await entity.render(request.copy(uri_path=()))
  File "/home/LP-HAW/.local/lib/python3.10/site-packages/aiocoap/resource.py", line 117, in render
    response = await m(request)
  File "/home/LP-HAW/.local/lib/python3.10/site-packages/aiocoap/cli/rd.py", line 407, in render_get
    return link_format_from_message(request, self.reg.links)
TypeError: link_format_from_message() takes 1 positional argument but 2 were given

To fix this error link_format_to_message should be called instead of link_format_from_message

[chrysn]

Thanks, merged.