Remove extra newline in errors.pot from installer template

[rhcarvalho]

After creating a new project, running mix gettext.extract --merge would remove that line anyway, causing an unnecessary change.

Related to #5649.

[rhcarvalho]

I tried writing a test for this but was not successful.

Specifically, I changed test "new with defaults" in installer/test/phx_new_test.exs. I wanted to add a step to run mix gettext.extract --merge or mix gettext.extract --check-up-to-date, but was not able to get things to work.

Snapshot of some things I tried

      # ...

      # Gettext
      assert_file("phx_blog/lib/phx_blog_web/gettext.ex", ~r"defmodule PhxBlogWeb.Gettext")
      assert File.exists?("phx_blog/priv/gettext/errors.pot")
      assert File.exists?("phx_blog/priv/gettext/en/LC_MESSAGES/errors.po")

      Mix.Project.in_project(:phx_blog, "phx_blog", fn _module ->
        Mix.Tasks.Deps.Get.run(~w(--only dev))
        # Mix.Task.run("gettext.extract", ["--check-up-to-date"])
      end)

      # generated_errors_pot = File.read!("phx_blog/priv/gettext/errors.pot")
      # Mix.Tasks.Gettext.Extract.run(["--merge"])
      # assert generated_errors_pot == File.read!("phx_blog/priv/gettext/errors.pot")

Those tasks would require deps to be fetched, but that might be undesirable, as it would make the tests slower, dependent on network and possibly flaky.

It also seems wrong to require mix gettext.extract --check-up-to-date to pass. I think it is okay to require a first call to mix gettext.extract --merge to update gettext files after the project is generated.

[josevalim]

💚 💙 💜 💛 ❤️