message: chore: don't print heading with the section is empty
diff: @@ -128,6 +128,7 @@ def compare_aa_muts(new, old):
  msg += f"\nAA deletions removed : {dels_removed}"
  msg += "\n\n"
  + if msg:
  print_with_heading('aaSubstitutions & aaDeletions', msg)
  