Preserve non-ASCII whitespace characters in HTML (#8137)
* Add html whitespace tests
* `U+0005` -> `U+2005`
* Update tests
* Fix whitespace
* Add changelog
* Another space
* Restore `non-breaking` check
* Add space between tests
* Extract all space related codes to utils
* Fix indent detect
* Update changelog
* Another space
* Rename
* Rename
* Rename
* Use `htmlTrimFirstLine` and `htmlTrimEnd`
* Assert with output
* `htmlTrimPreserveIndentation`
* Update changelog
* Fix another space