pythongh-95273: Clarify when sqlite_* attributes are added to sqlite3 exceptions (pythonGH-95523)

(cherry picked from commit 1e6b635)

Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@protonmail.com>

Author: erlend-aasland

Doc/library/sqlite3.rst

@@ -1310,6 +1310,9 @@ The exception hierarchy is defined by the DB-API 2.0 (:pep:`249`).
    Use this to catch all errors with one single :keyword:`except` statement.
    ``Error`` is a subclass of :exc:`Exception`.
 
+   If the exception originated from within the SQLite library,
+   the following two attributes are added to the exception:
+
    .. attribute:: sqlite_errorcode
 
       The numeric error code from the