feat: NoEmptyPhpdocFixer - do not leave empty line after removing PHPDoc

[kubawerlos]

NoEmptyPhpdocFixer (priority 3) should run before ClassAttributesSeparationFixer priority 55) - proof:

echo '<?php
class Foo
{
    public function f1() {}

    /**
     */
    public function f1() {}
}' > test.php

php php-cs-fixer fix --diff -vvv test.php --rules='{"class_attributes_separation":{"elements":{"method":"one"}}, "no_empty_phpdoc": true}'
php php-cs-fixer fix --diff -vvv test.php --rules='{"class_attributes_separation":{"elements":{"method":"one"}}, "no_empty_phpdoc": true}'
rm test.php

But it can't:

• ClassAttributesSeparationFixer must run before IndentationTypeFixer
• IndentationTypeFixer must run before PhpdocIndentFixer
• PhpdocIndentFixer must run before NoEmptyPhpdocFixer
  (probably not the only blocker)

So, let's remove the line when removing PHPDoc (if possible).

Ref. #3604

[coveralls]

coverage: 94.774% (+0.002%) from 94.772%
when pulling 3f451c7 on 6b7562617765726c6f73:feat_NoEmptyPhpdocFixer
into 13df1fc on PHP-CS-Fixer:master.