pgsql: Fix a couple of typos

Fix a couple of typos

PL/pgSQL was misspelled in a few places, so fix these.

Author: Zhang Mingli
Reviewed-by: Richard Guo
Discussion: https://postgr.es/m/1bd41572-9cd9-465e-9f59-ee45385e51b4@Spark

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/88199b9d5fda605360ac903dd9d3de0ca36f0b8c

Modified Files
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src/pl/plpython/expected/plpython_ereport.out | 2 +-
src/pl/plpython/sql/plpython_ereport.sql      | 2 +-
src/test/modules/test_pg_dump/t/001_base.pl   | 6 +++---
3 files changed, 5 insertions(+), 5 deletions(-)