Preserve standalone version catalog comments

[aoto-tech]

Fixes #3048.

Summary

• preserve standalone comments at section boundaries and EOF
• keep trailing comments attached to their originating section when tables are sorted
• ignore terminal blank lines so the formatter does not add extra newlines

Testing

• ./gradlew.bat :testlib:test --tests com.diffplug.spotless.toml.VersionCatalogStepTest --no-daemon --no-configuration-cache --no-build-cache --max-workers=1 (38 tests passed)
• ./gradlew.bat :lib:spotlessJavaCheck :testlib:spotlessJavaCheck --no-daemon --no-configuration-cache --no-build-cache --max-workers=1
• git diff --check

[aoto-tech]

wait Reviewers status!