Apply suggestions from code review

Co-authored-by: Adam Turner <[email protected]>

Lib/test/test_tools/test_i18n/test_i18n.py

@@ -63,14 +63,14 @@ def assert_POT_equal(self, expected, actual):
         expected = re.sub(date_pattern, header, expected)
         actual = re.sub(date_pattern, header, actual)
 
-        # Normalize charset (currently there's no way to specify the output charset)
+        # Normalize charset to UTF-8 (currently there's no way to specify the output charset)
         charset_pattern = re.compile(r'"Content-Type: text/plain; charset=.+?\n"')
         charset = "Content-Type: text/plain; charset=UTF-8\\n"
         expected = re.sub(charset_pattern, charset, expected)
         actual = re.sub(charset_pattern, charset, actual)
 
         # Normalize the file location path separators in case this test is
-        # running on a platform which does not use '/' as a default separator
+        # running on Windows (which uses '\')
         fileloc_pattern = re.compile(r'#:.+')
 
         def replace(match):
@@ -349,7 +349,7 @@ def test_pygettext_output(self):
                 contents = (data_dir / input_file).read_text(encoding='utf-8')
                 with temp_cwd(None):
                     Path(input_file).write_text(contents)
-                    assert_python_ok(self.script, '-D', input_file)
+                    assert_python_ok(self.script, '--docstrings', input_file)
                     output = Path('messages.pot').read_text()
 
                 expected = (data_dir / output_file).read_text(encoding='utf-8')