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/membership/members_pdf.ex

@@ -299,11 +299,9 @@ defmodule Mv.Membership.MembersPDF do
   defp date_column?(_), do: false
 
   defp key_to_atom_safe(key) when is_binary(key) do
-    try do
-      String.to_existing_atom(key)
-    rescue
-      ArgumentError -> key
-    end
+    String.to_existing_atom(key)
+  rescue
+    ArgumentError -> key
   end
 
   defp key_to_atom_safe(key), do: key