Re: Document How Commit Handles Aborted Transactions

The following review has been posted through the commitfest application:
make installcheck-world:  tested, failed
Implements feature:       tested, failed
Spec compliant:           tested, failed
Documentation:            tested, failed

Summary:
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The patch adds documentation to clarify how PostgreSQL handles aborted transactions during the commit process. The
changesare clear and improve the existing documentation.
 

Testing:
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1. Manually applied the patch to the latest master branch (commit 4cffc93).
2. Fixed SGML structure issues in `advanced.sgml` and `commit.sgml` by wrapping `<varlistentry>` in `<variablelist>`.
3. Rebuilt the documentation using `make html`.
4. Verified the new sections are present and correctly formatted in the generated HTML.

Feedback:
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- The patch was manually applied due to conflicts in `advanced.sgml` and `commit.sgml`.
- Fixed invalid SGML structure by wrapping `<varlistentry>` in `<variablelist>`.
- The documentation is accurate and follows PostgreSQL’s style guidelines.
- No additional issues were found.

Recommendation:
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Ready for committer. No objections.

The new status of this patch is: Ready for Committer