bpo-43853: Amend NEWS entry for latest changes in sqlite3 (GH-27922)

Author: Erlend Egeberg Aasland

Misc/NEWS.d/next/Library/2021-04-15-12-02-17.bpo-43853.XXCVAp.rst

@@ -1,3 +1,7 @@
-Improve :mod:`sqlite3` error handling: ``sqlite3_value_text()`` errors that
-set ``SQLITE_NOMEM`` now raise :exc:`MemoryError`. Patch by Erlend E.
-Aasland.
+Improved string handling for :mod:`sqlite3` user-defined functions and
+aggregates:
+
+* It is now possible to pass strings with embedded null characters to UDFs
+* Conversion failures now correctly raise :exc:`MemoryError`
+
+Patch by Erlend E. Aasland.