Fix Quoted Literals for Postgres and Redshift affecting rule L039

[tunetheweb]

Brief summary of the change made

Fixes #2495 - prevent final comma being swallowed up
Fixes #2516 - move DollarQuotedLiteralSegment into QuotedLiteralSegment

A potential nicer fix to #2495 would be to have an alternative to allow_trailing option, which doesn't error when there is a trailing delimiter, but recognised this is not part of this Grammar. But had a quick look and can't figure out how to do that.

Are there any other side effects of this change that we should be aware of?

No

Pull Request checklist

• Please confirm you have completed any of the necessary steps below.

• Included test cases to demonstrate any code changes, which may be one or more of the following:

  • .yml rule test cases in test/fixtures/rules/std_rule_cases.
  • .sql/.yml parser test cases in test/fixtures/dialects (note YML files can be auto generated with tox -e generate-fixture-yml).
  • Full autofix test cases in test/fixtures/linter/autofix.
  • Other.

• Added appropriate documentation for the change.

• Created GitHub issues for any relevant followup/future enhancements if appropriate.

[codecov]

Codecov Report

Merging #2526 (fdf35ce) into main (c744e20) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main     #2526   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          162       162           
  Lines        11700     11700           
=========================================
  Hits         11700     11700           

Impacted Files	Coverage Δ
src/sqlfluff/dialects/dialect_postgres.py	100.00% <ø> (ø)

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[barrywhart]

Looks great!

[jpy-git]

A potential nicer fix to #2495 would be to have an alternative to allow_trailing option, which doesn't error when there is a trailing delimiter, but recognised this is not part of this Grammar. But had a quick look and can't figure out how to do that.

I actually tried this the other day and it worked fine in terms of not including but not failing on a trailing delimiter and when I tested the grammar on it's own it would work. But whenever I tried parsing some actual SQL it would still get included in the expression 🤷 Your solution works well though 👍

[tunetheweb]

Glad I didn't work too hard on that then! 😁

Would be nice to look at Delimted at some point to stop being sooo Greedy (e.g. ignore commas in brackets), and also for this use case.