gh-94321: Document sqlite3.PrepareProtocol

Doc/library/sqlite3.rst

@@ -1140,6 +1140,15 @@ Blob Objects
       end).
 
 
+.. _sqlite3-prepareprotocol-objects:
+
+.. class:: PrepareProtocol
+
+The PrepareProtocol type's single purpose is to act as a :pep:`246` style
+adaption protocol for objects that can :ref:`adapt themselves
+<sqlite3-conform>` to :ref:`native SQLite types <sqlite3-types>`.
+
+
 .. _sqlite3-exceptions:
 
 Exceptions
@@ -1298,6 +1307,8 @@ As an application developer, it may make more sense to take direct control by
 registering custom adapter functions.
 
 
+.. _sqlite3-conform
+
 Letting your object adapt itself
 """"""""""""""""""""""""""""""""
 

Modules/_sqlite/prepare_protocol.c

@@ -46,10 +46,13 @@ pysqlite_prepare_protocol_dealloc(pysqlite_PrepareProtocol *self)
     Py_DECREF(tp);
 }
 
+PyDoc_STRVAR(doc, "sqlite3 object adaption protocol type");
+
 static PyType_Slot type_slots[] = {
     {Py_tp_dealloc, pysqlite_prepare_protocol_dealloc},
     {Py_tp_init, pysqlite_prepare_protocol_init},
     {Py_tp_traverse, pysqlite_prepare_protocol_traverse},
+    {Py_tp_doc, (void *)doc},
     {0, NULL},
 };