Fix follow_redirect/3 doc example for regular redirects (#4187)

* Fix follow_redirect/3 doc example for regular redirects

* Use :live_redirect in follow_redirect docs

Author: preciz

lib/phoenix_live_view/test/live_view_test.ex

@@ -1831,7 +1831,7 @@ defmodule Phoenix.LiveViewTest do
 
   Or in the case of an error tuple:
 
-      assert {:error, {:redirect, %{to: "/somewhere"}}} = result = live(conn, "my-path")
+      assert {:error, {:live_redirect, %{to: "/somewhere"}}} = result = live(conn, "my-path")
       {:ok, view, html} = follow_redirect(result, conn)
 
   `follow_redirect/3` expects a connection as second argument.