Fix typos

test/-ext-/struct/test_duplicate.rb

@@ -3,7 +3,7 @@ require 'test/unit'
 require "-test-/struct"
 
 class Bug::Struct::Test_Duplicate < Test::Unit::TestCase
-  def test_new_dupilicate
+  def test_new_duplicate
     bug12291 = '[ruby-core:74971] [Bug #12291]'
     assert_raise_with_message(ArgumentError, /duplicate member/, bug12291) {
       Bug::Struct.new_duplicate(nil, "a")
@@ -13,7 +13,7 @@ class Bug::Struct::Test_Duplicate < Test::Unit::TestCase
     }
   end
 
-  def test_new_dupilicate_under
+  def test_new_duplicate_under
     bug12291 = '[ruby-core:74971] [Bug #12291]'
     assert_raise_with_message(ArgumentError, /duplicate member/, bug12291) {
       Bug::Struct.new_duplicate_under("x", "a")