fix: keep \u2028, \u2029, \ufeff escaped when unescape_strings is true

[Saima422]

Description

• Source branch in your fork has meaningful name (not main)

Fixes Issue: #2141

Before Merge Checklist

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(Check any items that are not applicable (NA) for this PR)

• JavaScript implementation
• Python implementation (NA if HTML beautifier)
• Added Tests to data file(s) - N/A
• Added command-line option(s) - N/A
• README.md documents new feature/option(s) - N/A

[sirati]

I would like to caution against just doing a band-aid fix on the particular failure case that I have encountered. To do this properly would likely entail to re-escape characters based on their unicode properties, the same way a E6/JS parser would use the Unicode properties to decide what characters create count as a new line, or otherwise have special syntactic meaning.