Fix Credo Readability (strict)

- Max line length, implicit try, alias order, zero-arity defs
- String sigils, long comments split; redundant blank lines fixed

lib/mv_web/controllers/member_export_controller.ex

@@ -14,8 +14,8 @@ defmodule MvWeb.MemberExportController do
   alias Mv.Membership.CustomField
   alias Mv.Membership.Member
   alias Mv.Membership.MembersCSV
-  alias MvWeb.Translations.MemberFields
   alias MvWeb.MemberLive.Index.MembershipFeeStatus
+  alias MvWeb.Translations.MemberFields
   use Gettext, backend: MvWeb.Gettext
 
   @member_fields_allowlist (Mv.Constants.member_fields() |> Enum.map(&Atom.to_string/1)) ++
@@ -105,12 +105,10 @@ defmodule MvWeb.MemberExportController do
   end
 
   defp atom_exists?(name) do
-    try do
-      _ = String.to_existing_atom(name)
-      true
-    rescue
-      ArgumentError -> false
-    end
+    _ = String.to_existing_atom(name)
+    true
+  rescue
+    ArgumentError -> false
   end
 
   defp extract_list(params, key) do