bug#47788: Add support for TLS client certificates to 'erc-tls'

["J.P." <jp@neverwas.me>]

Hey, guess we both missed this:

  @@ -505,18 +512,23 @@ erc-server-process-alive
            (memq (process-status erc-server-process) '(run open)))))
   
   ;;;; Connecting to a server
  -(defun erc-open-network-stream (name buffer host service)
  -  "As `open-network-stream', but does non-blocking IO"
  -  (make-network-process :name name :buffer  buffer
  -                        :host host :service service :nowait t))
  +(defun erc-open-network-stream (name buffer host service &rest parameters)
  +  "Like `open-network-stream', but does non-blocking IO."
  +  (let ((p (plist-put parameters :nowait t)))
  +    (open-network-stream name buffer host service p)))
     ;; ^~~~~~~~ Need an apply #' here because ~~~~~~^
   
  -(defun erc-server-connect (server port buffer)
  +(defun erc-server-connect (server port buffer &optional client-certificate)

Turns out my silly tests for one of those unofficial #erc bugs (the
azur12 one) caught it by failing (which means your patch magically fixed
the issue!).

Anyway, no rush; I doubt this really impacts anyone.