doc: PG 16 relnotes, add commits

Reported-by: Ian Lawrence Barwick

Discussion: https://postgr.es/m/CAB8KJ=hLvQDb53WdigV7OBEBh5tzQ7eA=pG0ZpccoRVBUNCXYA@mail.gmail.com

Author: bmomjian

doc/src/sgml/release-16.sgml

@@ -233,6 +233,8 @@ Allow incremental sorts in more cases, including DISTINCT (David Rowley)
 
 <!--
 Author: David Rowley <drowley@postgresql.org>
+2022-08-02 [1349d2790] Improve performance of ORDER BY / DISTINCT aggregates
+Author: David Rowley <drowley@postgresql.org>
 2022-12-20 [3226f4728] Add enable_presorted_aggregate GUC
 Author: David Rowley <drowley@postgresql.org>
 2023-01-17 [da5800d5f] Don't presort ORDER BY/DISTINCT Aggrefs with volatile fu
@@ -1632,6 +1634,8 @@ This can improve readability for long strings of digits.
 
 <!--
 Author: Tom Lane <tgl@sss.pgh.pa.us>
+2023-01-01 [2ceea5adb] Accept "+infinity" in date and timestamp[tz] input.
+Author: Tom Lane <tgl@sss.pgh.pa.us>
 2023-03-09 [bcc704b52] Reject combining "epoch" and "infinity" with other datet
 -->