pgsql: doc: avoid saying "inheritance" ...

doc: avoid saying "inheritance" ...

... when it applies to partitioned relations.  This is almost the
opposite of 0c06534bd63b, which removed references to "partition" in
favour of "child".

Author: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Reviewed-by: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/20220525013248.GO19626@telsasoft.com

Branch
------
REL_15_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/02e5c273a2dc9e4c2c59d05a030e74552f897210

Modified Files
--------------
doc/src/sgml/catalogs.sgml     | 10 +++++-----
doc/src/sgml/system-views.sgml |  6 +++---
2 files changed, 8 insertions(+), 8 deletions(-)