Remove invalid XML characters

[egoist]

Is your feature request related to a problem? Please describe. When writing a post it happens a lot that it might contain invalid XML characters

Describe the solution you'd like Remove those invalid characters in the output of this library, so it's fixed for everyone

Describe alternatives you've considered Let end users handle this

Additional context https://stackoverflow.com/questions/397250/unicode-regex-invalid-xml-characters/961504#961504 https://www.ryadel.com/en/javascript-remove-xml-invalid-chars-characters-string-utf8-unicode-regex/ https://github.com/saberland/saber/issues/537