pgsql: Correct some SQL feature names

Correct some SQL feature names

Maybe these were initially typos or they have been changed upstream
since we first added them. This brings it all in line with SQL:2016.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d94f29cb8910a380caa795f56e69ed036fb8c5d0

Modified Files
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src/backend/catalog/sql_features.txt | 50 ++++++++++++++++++------------------
1 file changed, 25 insertions(+), 25 deletions(-)