Issue3950: Fix docs for default locale used by gettext to match implementation (#18435)

documentation for default locale directory Doc/library/gettext.rst changed to match gettext implementation line 63.
diff --git a/Doc/library/gettext.rst b/Doc/library/gettext.rst
index 937330b..ec2c128 100644
--- a/Doc/library/gettext.rst
+++ b/Doc/library/gettext.rst
@@ -724,8 +724,8 @@
 .. [#] The default locale directory is system dependent; for example, on RedHat Linux
    it is :file:`/usr/share/locale`, but on Solaris it is :file:`/usr/lib/locale`.
    The :mod:`gettext` module does not try to support these system dependent
-   defaults; instead its default is :file:`{sys.prefix}/share/locale` (see
-   :data:`sys.prefix`). For this reason, it is always best to call
+   defaults; instead its default is :file:`{sys.base_prefix}/share/locale` (see
+   :data:`sys.base_prefix`). For this reason, it is always best to call
    :func:`bindtextdomain` with an explicit absolute path at the start of your
    application.