Fix FunctionNames for private sigils

Refs #1146

Author: rrrene

lib/credo/check/readability/function_names.ex

@@ -66,7 +66,7 @@ defmodule Credo.Check.Readability.FunctionNames do
            _issue_meta,
            _allow_acronyms?
          )
-         when op in [:def, :defmacro] do
+         when op in [:def, :defmacro, :defmacrop] do
       {ast, issues}
     end
 
@@ -77,7 +77,7 @@ defmodule Credo.Check.Readability.FunctionNames do
            _issue_meta,
            _allow_acronyms?
          )
-         when op in [:def, :defmacro] do
+         when op in [:def, :defmacro, :defmacrop] do
       {ast, issues}
     end
   end

test/credo/check/readability/function_names_test.exs

@@ -69,6 +69,8 @@ defmodule Credo.Check.Readability.FunctionNamesTest do
     defmacro sigil_U({:<<>>, _, [string]}, []) when is_binary(string) do
       # ...
     end
+    defmacrop sigil_d(str, _opts) do
+    end
     """
     |> to_source_file
     |> run_check(@described_check)