[JP] Update translation in mix lesson (#440)
[JP] Update translation in mix lesson (#440)

Apply changes in #236
yuriibodarev/elixir-school,ElixirVietnam/elixir-school,doomspork/elixir-school,psantos10/elixir-school,doomspork/elixir_school,doomspork/elixir-school,nscyclone/elixir-school,erickgnavar/elixir-school,huydx/elixir-school,nscyclone/elixir-school,ElixirVietnam/elixir-school,huydx/elixir-school,doomspork/elixir-school,yuriibodarev/elixir-school,doomspork/elixir_school,doomspork/elixir_school,yuriibodarev/elixir-school,psantos10/elixir-school,erickgnavar/elixir-school,ElixirVietnam/elixir-school,holsky/elixir-school,holsky/elixir-school,erickgnavar/elixir-school,holsky/elixir-school,nscyclone/elixir-school,psantos10/elixir-school,nscyclone/elixir-school,huydx/elixir-school