pgsql: psql: set SHELL_ERROR and SHELL_EXIT_CODE in more places.

psql: set SHELL_ERROR and SHELL_EXIT_CODE in more places.

Make the \g, \o, \w, and \copy commands set these variables
when closing a pipe.  We missed doing this in commit b0d8f2d98,
but it seems like a good idea.

There are some remaining places in psql that intentionally don't
update these variables after running a child program:
        * pager invocations
        * backtick evaluation within a prompt
        * \e (edit query buffer)

Corey Huinker and Tom Lane

Discussion: https://postgr.es/m/CADkLM=eSKwRGF-rnRqhtBORRtL49QsjcVUCa-kLxKTqxypsakw@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/31ae2aa9d2c200a0d7d3283d749669a408ec7b65

Modified Files
--------------
doc/src/sgml/ref/psql-ref.sgml | 16 ++++++++++++----
src/bin/psql/command.c         | 16 ++--------------
src/bin/psql/common.c          | 26 +++++++++++++++++++++++---
src/bin/psql/common.h          |  2 ++
src/bin/psql/copy.c            |  1 +
src/bin/psql/psqlscanslash.l   | 10 ++++------
6 files changed, 44 insertions(+), 27 deletions(-)