Make page_title/2 private in all LiveViews

The Index modules were calling Show.page_title/2 for modal edit
routes. Inlined the logic as private functions in each Index
module and removed the now-unused Show aliases.

Closes #104

lib/music_library_web/live/collection_live/show.ex

@@ -474,7 +474,7 @@ defmodule MusicLibraryWeb.CollectionLive.Show do
      |> assign_embedding_text()}
   end
 
-  def page_title(:show, record) do
+  defp page_title(:show, record) do
     Enum.join(
       [
         Records.Record.artist_names(record),
@@ -489,7 +489,7 @@ defmodule MusicLibraryWeb.CollectionLive.Show do
     )
   end
 
-  def page_title(action, record) do
+  defp page_title(action, record) do
     Enum.join(
       [
         Records.Record.artist_names(record),