Remove mention to confusing RFC

Author: picnixz

Misc/NEWS.d/next/Documentation/2025-01-14-11-06-41.gh-issue-67206.LYKmi5.rst

@@ -1,3 +1,3 @@
-Document that :const:`string.printable` is neither printable in the sense of
-POSIX nor of :rfc:`5822` In particular, :meth:`string.printable.isprintable()
-<str.isprintable>` returns :const:`False`. Patch by Bénédikt Tran.
+Document that :const:`string.printable` is not printable in the POSIX sense.
+In particular, :meth:`string.printable.isprintable() <str.isprintable>` returns
+:const:`False`. Patch by Bénédikt Tran.