pgsql: Fix incorrectly spelled city name

Fix incorrectly spelled city name

The correct spelling is Beijing, fix in regression test
and docs.

Author: JiaoShuntian <jiaoshuntian@gmail.com>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/ebfa3ec2-dc3c-4adb-be2a-4a882c2e85a7@gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/a9123db14a12e2e2dfb93dbbef4f2cdc2986023b

Modified Files
--------------
doc/src/sgml/ref/alter_table.sgml             |  2 +-
src/test/regress/expected/partition_merge.out | 16 +++++++-------
src/test/regress/expected/partition_split.out | 30 +++++++++++++--------------
src/test/regress/sql/partition_merge.sql      |  6 +++---
src/test/regress/sql/partition_split.sql      | 26 +++++++++++------------
5 files changed, 40 insertions(+), 40 deletions(-)