Include special packages in package_names.csv

The package_names.csv published to hexdocs.pm was generated solely from
the Hex registry names, so the Elixir standard library applications and
Hex itself (the special packages, which are documented on hexdocs.pm but
not published as Hex packages) were absent. Consumers such as the
hexdocs search autocomplete therefore could not list them.

Prepend the configured special package names so the file reflects the
same authoritative set the rest of the producer uses.

Author: ericmj

lib/hexdocs/queue.ex

@@ -362,6 +362,7 @@ defmodule Hexdocs.Queue do
 
     case Hexdocs.HexRepo.get_names() do
       {:ok, names} ->
+        names = Enum.sort(@special_package_names) ++ names
         csv = for name <- names, do: [name, "\n"]
         Hexdocs.Bucket.upload_package_names_csv(csv)
 

test/hexdocs/queue_test.exs

@@ -77,7 +77,15 @@ defmodule Hexdocs.QueueTest do
 
       assert Store.get(@public_bucket, "#{test}/index.html") == "contents"
       assert Store.get(@public_bucket, "#{test}/1.0.0/index.html") == "contents"
-      assert Store.get(@public_bucket, "package_names.csv") == "package1\npackage2\n"
+      names = Store.get(@public_bucket, "package_names.csv") |> String.split("\n", trim: true)
+      assert "package1" in names
+      assert "package2" in names
+
+      special_packages = Map.keys(Application.fetch_env!(:hexdocs, :special_packages))
+
+      for package <- special_packages do
+        assert package in names
+      end
     end
 
     test "overwrite main docs with newer versions", %{test: test} do