pgsql: psql: Add quit/help behavior/hint, for other tool portability

psql: Add quit/help behavior/hint, for other tool portability Issuing 'quit'/'exit' in an empty psql buffer exits psql. Issuing 'quit'/'exit' in a non-empty psql buffer alone on a line with no prefix whitespace issues a hint on how to exit. Also add similar 'help' hints for 'help' in a non-empt

pgsql: Fix possible failure to mark hash metapage dirty.

Fix possible failure to mark hash metapage dirty. Report and suggested fix by Lixian Zou. Amit Kapila put it in the form of a patch and reviewed. Discussion: http://postgr.es/m/[email protected] Branch -- master Details --- https://git.post

pgsql: Fix possible failure to mark hash metapage dirty.

Fix possible failure to mark hash metapage dirty. Report and suggested fix by Lixian Zou. Amit Kapila put it in the form of a patch and reviewed. Discussion: http://postgr.es/m/[email protected] Branch -- REL_10_STABLE Details --- https://g