Trim the test comment and tighten the NEWS wording

Author: tonghuaroot

Lib/test/test_csv.py

@@ -1464,9 +1464,7 @@ def test_sniff(self):
         self.assertIs(dialect.skipinitialspace, False)
 
     def test_sniff_delimiter_equals_quotechar(self):
-        # A sample that makes sniff() guess a dialect whose delimiter equals
-        # its quotechar is invalid; that must surface as csv.Error, not as a
-        # raw ValueError leaking from the _csv extension.
+        # An inconsistent guessed dialect must surface as csv.Error.
         sniffer = csv.Sniffer()
         for sample in ('"', '""', "''"):
             with self.subTest(sample=sample):

Misc/NEWS.d/next/Library/2026-07-09-16-41-20.gh-issue-153634.27Fs4T.rst

@@ -1,4 +1,4 @@
 :meth:`csv.Sniffer.sniff` now raises :exc:`csv.Error` for an inconsistent
-guessed dialect, for example one whose delimiter equals its quote character,
-instead of returning it. :meth:`csv.Sniffer.has_header` now raises
-:exc:`csv.Error` instead of leaking a :exc:`ValueError`.
+guessed dialect (one whose delimiter equals its quote character) instead of
+returning it. :meth:`csv.Sniffer.has_header` now raises :exc:`csv.Error`
+instead of leaking a :exc:`ValueError`.