pgsql: Record parents of triggers

Record parents of triggers

This let us get rid of a recently introduced ugly hack (commit
1fa846f1c9af).

Author: Álvaro Herrera
Reviewed-by: Amit Langote, Tom Lane
Discussion: https://postgr.es/m/20200217215641.GA29784@alvherre.pgsql

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b9b408c487244ef8e6d613d183c56eb2c62990b1

Modified Files
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doc/src/sgml/catalogs.sgml                 | 11 ++++++
src/backend/commands/tablecmds.c           | 59 +++---------------------------
src/backend/commands/trigger.c             |  1 +
src/include/catalog/pg_trigger.h           |  1 +
src/test/regress/expected/sanity_check.out |  3 ++
src/test/regress/expected/triggers.out     |  9 +++++
src/test/regress/sql/triggers.sql          | 10 +++++
7 files changed, 40 insertions(+), 54 deletions(-)