Fixed coding standard error

Author: gsherwood

src/Standards/PSR12/Sniffs/Files/FileHeaderSniff.php

@@ -147,7 +147,7 @@ public function process(File $phpcsFile, $stackPtr)
                 $next = $phpcsFile->findNext(T_WHITESPACE, ($line['end'] + 1), null, true);
                 if ($tokens[$next]['line'] !== ($tokens[$line['end']]['line'] + 2)) {
                     $error = 'Header blocks must be followed by a single blank line';
-                    $fix = $phpcsFile->addFixableError($error, $line['end'], 'SpacingAfterBlock');
+                    $fix   = $phpcsFile->addFixableError($error, $line['end'], 'SpacingAfterBlock');
                     if ($fix === true) {
                         if ($tokens[$next]['line'] === $tokens[$line['end']]['line']) {
                             $phpcsFile->fixer->addNewlineBefore($next);