Deprecation of FILTER_SANITIZE_STRING

[SpottedPaint]

In PHP 8.1 FILTER_SANITIZE_STRING seems to be deprecated.
They suggest swapping for htmlspecialchars but that doesn't seem to be an exact swap.
https://www.php.net/manual/en/filter.filters.sanitize.php

I've swapped line 106 in my installations login-nocaptcha.php
from
return trim(filter_var($string, FILTER_SANITIZE_STRING)); //must consist of valid string characters
to
return trim(htmlspecialchars(strip_tags($string), ENT_QUOTES, null, false));

There is a discussion on stack overflow here https://stackoverflow.com/questions/69207368/constant-filter-sanitize-string-is-deprecated

My messy testing file is which shows some of the differences, FILTER_SANITIZE_FULL_SPECIAL_CHARS seems to act quite differently with tags:
`
$strings = array();
$strings[] =" Start Tags: SingleQuote:'".' Tag With Attribute:<span="classname"> Encoded Less Than:< End';
$strings[] ='Start DoubleQuote:" End ';
$strings[] ='Start 中文 End ';
foreach($strings as $string){

	$specialChars = trim(htmlspecialchars(strip_tags($string), ENT_QUOTES, null, false));
	echo PHP_EOL;
	$filtered =  trim(@filter_var($string, FILTER_SANITIZE_STRING));
	$filteredAlternative = trim(filter_var($string, FILTER_SANITIZE_FULL_SPECIAL_CHARS));
	
	echo PHP_EOL;
	echo 'S:'.$specialChars.PHP_EOL;
	echo 'F:'.$filtered.PHP_EOL;
	echo 'A:'.$filteredAlternative.PHP_EOL;
}

`

[cyberscribe]

Thanks we would welcome a pull request