PG 16 draft release notes ready

I have completed the first draft of the PG 16 release notes.  You can
see the output here:

    https://momjian.us/pgsql_docs/release-16.html

I will adjust it to the feedback I receive;  that URL will quickly show
all updates.

I learned a few things creating it this time:

*  I can get confused over C function names and SQL function names in
   commit messages.

*  The sections and ordering of the entries can greatly clarify the
   items.

*  The feature count is slightly higher than recent releases:

    release-10:  189
    release-11:  170
    release-12:  180
    release-13:  178
    release-14:  220
    release-15:  184
-->    release-16:  200

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.