Reset $annotations keys before determining the last content end pointer

```php
var_dump($annotations, $annotations[$annotationsCount - 1]->getEndPointer(), $firstContentEndPointer, $lastContentEndPointer);
```

Before:

array(3) {
        [0] =>
      class SlevomatCodingStandard\Helpers\Annotation#319 (5) {
        private $name =>
        string(5) "@link"
        private $startPointer =>
        int(4974)
        private $endPointer =>
        int(4976)
        private $parameters =>
        NULL
        private $content =>
        string(146) "https://github.com/..."
      }
      [2] =>
      class SlevomatCodingStandard\Helpers\Annotation#317 (5) {
        private $name =>
        string(5) "@todo"
        private $startPointer =>
        int(4984)
        private $endPointer =>
        int(4986)
        private $parameters =>
        NULL
        private $content =>
        string(27) "TODO."
      }
      [1] =>
      class SlevomatCodingStandard\Helpers\Annotation#320 (5) {
        private $name =>
        string(5) "@link"
        private $startPointer =>
        int(4994)
        private $endPointer =>
        int(4996)
        private $parameters =>
        NULL
        private $content =>
        string(40) "https://..."
      }
    }
    int(4986)
    int(4969)
    int(4986)

After:

    array(3) {
        [0] =>
      class SlevomatCodingStandard\Helpers\Annotation#319 (5) {
        private $name =>
        string(5) "@link"
        private $startPointer =>
        int(4974)
        private $endPointer =>
        int(4976)
        private $parameters =>
        NULL
        private $content =>
        string(146) "https://github.com/..."
      }
      [1] =>
      class SlevomatCodingStandard\Helpers\Annotation#317 (5) {
        private $name =>
        string(5) "@todo"
        private $startPointer =>
        int(4984)
        private $endPointer =>
        int(4986)
        private $parameters =>
        NULL
        private $content =>
        string(27) "TODO."
      }
      [2] =>
      class SlevomatCodingStandard\Helpers\Annotation#320 (5) {
        private $name =>
        string(5) "@link"
        private $startPointer =>
        int(4994)
        private $endPointer =>
        int(4996)
        private $parameters =>
        NULL
        private $content =>
        string(40) "https://..."
      }
    }
    int(4996)
    int(4969)
    int(4996)

Author: echernyavskiy

SlevomatCodingStandard/Sniffs/Commenting/DocCommentSpacingSniff.php

@@ -101,6 +101,7 @@ public function process(File $phpcsFile, $docCommentOpenPointer): void
 		uasort($annotations, function (Annotation $a, Annotation $b): int {
 			return $a->getStartPointer() <=> $b->getEndPointer();
 		});
+		$annotations = array_values($annotations);
 		$annotationsCount = count($annotations);
 
 		$firstAnnotation = $annotationsCount > 0 ? $annotations[0] : null;