[DOCS] Incorrect link in release notes

[M. Justin]

When reviewing the PostgreSQL 10 release notes I discovered that the
make_date() link in "E.1.3.6. Functions" incorrectly points to
https://www.postgresql.org/docs/devel/static/functions-formatting.html#functions-formatting-table
instead of
https://www.postgresql.org/docs/10/static/functions-datetime.html#functions-datetime-table
.