gh-141510: Mention frozendict in dict documentation (#144934)

test_genericalias now tests also frozendict.

Author: vstinner

Doc/library/stdtypes.rst

@@ -5590,8 +5590,8 @@ can be used interchangeably to index the same dictionary entry.
 
 
    .. seealso::
-      :class:`types.MappingProxyType` can be used to create a read-only view
-      of a :class:`dict`.
+      :class:`frozendict` and :class:`types.MappingProxyType` can be used to
+      create a read-only view of a :class:`dict`.
 
 .. _thread-safety-dict:
 

Lib/pydoc_data/topics.py

@@ -101,7 +101,8 @@
 
 class BaseTest(unittest.TestCase):
     """Test basics."""
-    generic_types = [type, tuple, list, dict, set, frozenset, enumerate, memoryview,
+    generic_types = [type, tuple, list, dict, frozendict,
+                     set, frozenset, enumerate, memoryview,
                      slice,
                      defaultdict, deque,
                      SequenceMatcher,