Add @deprecated to functions related to levelpad

Author: nallwhy

lib/logger/lib/logger/formatter.ex

@@ -160,12 +160,15 @@ defmodule Logger.Formatter do
   defp output(:node, _, _, _, _), do: Atom.to_string(node())
   defp output(:metadata, _, _, _, []), do: ""
   defp output(:metadata, _, _, _, meta), do: metadata(meta)
+  @deprecated "levelpad is deprecated"
   defp output(:levelpad, level, _, _, _), do: levelpad(level)
   defp output(other, _, _, _, _), do: other
 
-  # TODO: Deprecate me on Elixir v1.13+ or later
+  @deprecated "levelpad is deprecated"
   defp levelpad(:info), do: " "
+  @deprecated "levelpad is deprecated"
   defp levelpad(:warn), do: " "
+  @deprecated "levelpad is deprecated"
   defp levelpad(_), do: ""
 
   defp metadata([{key, value} | metadata]) do

lib/logger/test/logger/formatter_test.exs

@@ -90,6 +90,7 @@ defmodule Logger.FormatterTest do
              [["foo", 61, "bar", 32], " ", "hello"]
   end
 
+  @deprecated "levelpad is deprecated"
   test "padding takes account of length of level" do
     compiled = compile("[$level] $levelpad $message")
     assert format(compiled, :error, "hello", nil, []) == ["[", "error", "] ", "", " ", "hello"]