pgsql: Doc: update v14 release notes through today.

Doc: update v14 release notes through today. Account for recent commits, notably reversion of 0827e8af7. Strip trailing spaces. Branch -- REL_14_STABLE Details --- https://git.postgresql.org/pg/commitdiff/68b6ed42e69f920c67902e33d4a648bd39e0a19b Modified Files -- doc/src/sgm

pgsql: Doc: copy-editing for v14 release notes.

Doc: copy-editing for v14 release notes. Improve various item descriptions. Rearrange some things into (IMO) more logical order. Fix missing markup and dubious choices of link destinations. Drop a couple of items that were later back-patched or otherwise don't seem to need to be documented here