bpo-38096:  Complete the "structseq" and "named tuple" cleanup (GH-16010) (GH-16062)

(cherry picked from commit 4210ad5ebd5769f585035e022876e161cd0e9a3e)

Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>
diff --git a/Objects/structseq.c b/Objects/structseq.c
index 2c25e16..320bf08 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -1,5 +1,11 @@
-/* Implementation helper: a struct that looks like a tuple.  See timemodule
-   and posixmodule for example uses. */
+/* Implementation helper: a struct that looks like a tuple.
+   See timemodule and posixmodule for example uses.
+
+   The structseq helper is considered an internal CPython implementation
+   detail.  Docs for modules using structseqs should call them
+   "named tuples" (be sure to include a space between the two
+   words and add a link back to the term in Docs/glossary.rst).
+*/
 
 #include "Python.h"
 #include "pycore_tupleobject.h"