change is_null to $value compare to null
for consistency with #3520
Merge branch 'hotfix/#6643-is-null-removal'

Close #6643
Fixes cs : space after if and elseif in deep conditional
iirc, I already sent a request to php-cs-fixer repository for its feature but it won't be implemented because it require to much logic
space after close parenthesis
Merge branch 'hotfix/#6743-if-spacing-psr2-compliance'

Close #6743
PHPCS fixes for Zend\Dom
Merge branch 'cs/#6699-zend-dom-psr-2-compat'

Close #6699
Fixes typo