perf: Combine `map` & `join` into `map_join`

lib/medical_transcription/utilities.ex

@@ -16,7 +16,6 @@ defmodule MedicalTranscription.Utilities do
 
   def tally_to_string(tallied_enumerable) do
     tallied_enumerable
-    |> Enum.map(fn {key, value} -> "#{key} (#{value})" end)
-    |> Enum.join(", ")
+    |> Enum.map_join(", ", fn {key, value} -> "#{key} (#{value})" end)
   end
 end