Postgres: allow reserved keywords as bare column alias

[BenSatori]

PostgreSQL allows almost any keyword (SELECT, ANALYZE, LATERAL, AND, OR, COLLATE, ...) to be used as a bare (AS-less) column alias unless it is in a small set of keywords that require a leading AS.

See https://www.postgresql.org/docs/current/sql-keywords-appendix.html

Previously:
SELECT (SELECT c FROM tbl_name LIMIT 1) select;

(or analyze/lateral/and/or/collate)
failed to parse.

This PR fixes that

[BenSatori]

I also tested directly on pg the aliases in the tests @LucaCappelletti94 .

[codecov-commenter]

Codecov Report

❌ Patch coverage is 93.75000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 81.10%. Comparing base (560a13c) to head (e2f3873).

Files with missing lines	Patch %	Lines
src/parser/mod.rs	91.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2491   +/-   ##
=======================================
  Coverage   81.09%   81.10%           
=======================================
  Files          42       42           
  Lines       33684    33700   +16     
  Branches    33684    33700   +16     
=======================================
+ Hits        27316    27332   +16     
  Misses       2798     2798           
  Partials     3570     3570           

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[LucaCappelletti94]

Snowflake's is_column_alias returns true for any keyword not in its own list, so the new loop break accepts SELECT 1 AND and SELECT 1 OR. Snowflake reserves both (reserved keywords).

Do extend the keyword list, and add the necessary tests for them.

-            Keyword::FROM
+            Keyword::AND
+            | Keyword::FROM
             | Keyword::GROUP
             | Keyword::HAVING
             | Keyword::INTERSECT
             | Keyword::INTO
             | Keyword::MINUS
+            | Keyword::OR
             | Keyword::ORDER