Fix lineos=true breaking copy to clipboard

[nginx-jack]

Change selector used to the .highlight class
Add regex to remove line numbers
Update regex to remove carriage returns start and end of block

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• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md and CHANGELOG.md)