gh-137440: Update comment in Python/hamt.c on importing for testing (GH-137441)

Switch from `_testcapi` to `_testinternalcapi`.

diff --git a/Python/hamt.c b/Python/hamt.c
index 906149cc6cdbdcb2c7a4f3217b1bd0c637a7bb96..e372b1a1b4c18b1c188ca293e6eb53705716667e 100644 (file)
--- a/Python/hamt.c
+++ b/Python/hamt.c
@@ -256,9 +256,9 @@ Debug
 =====
 
 The HAMT datatype is accessible for testing purposes under the
-`_testcapi` module:
+`_testinternalcapi` module:
 
-    >>> from _testcapi import hamt
+    >>> from _testinternalcapi import hamt
     >>> h = hamt()
     >>> h2 = h.set('a', 2)
     >>> h3 = h2.set('b', 3)