gh-161415: Remove nonexistent related help topics in pydoc

The TYPES topic listed FILES, which was removed from Helper.topics in
Python 3.4, and the UNICODE topic listed unicode, the Python 2 built-in
type. help() finds no entry for either of them.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: andresdelfino

Lib/pydoc.py

@@ -2029,12 +2029,12 @@ class Helper:
 
     topics = {
         'TYPES': ('types', 'STRINGS UNICODE NUMBERS SEQUENCES MAPPINGS '
-                  'FUNCTIONS CLASSES MODULES FILES inspect'),
+                  'FUNCTIONS CLASSES MODULES inspect'),
         'STRINGS': ('strings', 'str UNICODE SEQUENCES STRINGMETHODS '
                     'FORMATTING TYPES'),
         'STRINGMETHODS': ('string-methods', 'STRINGS FORMATTING'),
         'FORMATTING': ('formatstrings', 'OPERATORS'),
-        'UNICODE': ('strings', 'encodings unicode SEQUENCES STRINGMETHODS '
+        'UNICODE': ('strings', 'encodings SEQUENCES STRINGMETHODS '
                     'FORMATTING TYPES'),
         'NUMBERS': ('numbers', 'INTEGER FLOAT COMPLEX TYPES'),
         'INTEGER': ('integers', 'int range'),

Lib/test/test_pydoc/test_pydoc.py

@@ -2294,6 +2294,20 @@ def test_keywords(self):
         self.assertEqual(sorted(pydoc.Helper.keywords),
                          sorted(keyword.kwlist + ['case', 'match', 'lazy']))
 
+    def test_related_topics(self):
+        # Every related help topic must be something help() can document.
+        helper = pydoc.Helper
+        for name, target in (*helper.topics.items(), *helper.keywords.items()):
+            if not isinstance(target, tuple):
+                continue
+            for xref in target[1].split():
+                with self.subTest(topic=name, xref=xref):
+                    self.assertTrue(xref in helper.topics
+                                    or xref in helper.keywords
+                                    or xref in helper.symbols
+                                    or xref == 'keywords'  # the keyword list
+                                    or pydoc.locate(xref) is not None)
+
     def test_interact_empty_line_continues(self):
         # gh-138568: test pressing Enter without input should continue in help session
         self.assertEqual(

Misc/NEWS.d/next/Library/2026-11-05-12-00-24.gh-issue-161415.NJhrAR.rst

@@ -0,0 +1,3 @@
+Remove ``FILES`` and ``unicode`` from the related help topics listed by
+:func:`help` for the ``TYPES`` and ``UNICODE`` topics. Neither exists in
+Python 3, so asking for help on them failed.