Mark helpers private

Author: Seldaek

src/Preg.php

@@ -277,7 +277,7 @@ public static function isMatchAllWithOffsets(string $pattern, string $subject, ?
         return (bool) static::matchAllWithOffsets($pattern, $subject, $matches, $flags, $offset);
     }
 
-    protected static function checkOffsetCapture(int $flags, string $useFunctionName): void
+    private static function checkOffsetCapture(int $flags, string $useFunctionName): void
     {
         if (($flags & PREG_OFFSET_CAPTURE) !== 0) {
             throw new \InvalidArgumentException('PREG_OFFSET_CAPTURE is not supported as it changes the type of $matches, use ' . $useFunctionName . '() instead');

src/Regex.php

@@ -112,7 +112,7 @@ public static function replaceCallbackArray(array $pattern, $subject, int $limit
         return new ReplaceResult($count, $result);
     }
 
-    protected static function checkOffsetCapture(int $flags): void
+    private static function checkOffsetCapture(int $flags): void
     {
         if (($flags & PREG_OFFSET_CAPTURE) !== 0) {
             throw new \InvalidArgumentException('PREG_OFFSET_CAPTURE is not supported as it changes the return type, use matchWithOffsets() instead');