Universal/NoFQNTrueFalseNull: fix for changed tokenization in PHPCS 3.13.3 and 4.0

The tokenization of fully qualified `true`/`false`/`null` has been changed for both PHPCS 3.x (as of 3.13.3) as well as PHPCS 4.0.

The new tokenization means we don't need to take these tokens being tokenized as `T_STRING` or `T_NAME_FULLY_QUALIFIED` into account anymore, as long as the minimum supported PHPCS version will be PHPCS 3.13.3.

However, we now do need to verify that `T_TRUE`/`T_FALSE`/`T_NULL` tokens don't have a namespace separator included in their contents.

This commit updates the sniff for these changes.

Ref:
* PHPCSStandards/PHP_CodeSniffer 1201
* PHPCSStandards/PHP_CodeSniffer 1206

Author: jrfnl

Universal/Sniffs/PHP/NoFQNTrueFalseNullSniff.php

@@ -32,16 +32,9 @@ final class NoFQNTrueFalseNullSniff implements Sniff
     public function register()
     {
         return [
-            // PHPCS 3.x on PHP < 8.0.
             \T_TRUE,
             \T_FALSE,
             \T_NULL,
-
-            // PHPCS 3.x on PHP >= 8.0.
-            \T_STRING,
-
-            // PHPCS 4.x.
-            \T_NAME_FULLY_QUALIFIED,
         ];
     }
 
@@ -62,17 +55,12 @@ public function process(File $phpcsFile, $stackPtr)
         $content   = $tokens[$stackPtr]['content'];
         $contentLC = \strtolower($content);
 
-        if ($tokens[$stackPtr]['code'] === \T_NAME_FULLY_QUALIFIED) {
+        $error = false;
+        if ($contentLC === '\true' || $contentLC === '\false' || $contentLC === '\null') {
             // PHPCS 4.x.
-            if ($contentLC !== '\true' && $contentLC !== '\false' && $contentLC !== '\null') {
-                return;
-            }
+            $error = true;
         } else {
             // PHPCS 3.x.
-            if ($contentLC !== 'true' && $contentLC !== 'false' && $contentLC !== 'null') {
-                return;
-            }
-
             $prev = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($stackPtr - 1), null, true);
             if ($tokens[$prev]['code'] !== \T_NS_SEPARATOR) {
                 return;
@@ -87,6 +75,12 @@ public function process(File $phpcsFile, $stackPtr)
             if ($tokens[$next]['code'] === \T_NS_SEPARATOR) {
                 return;
             }
+
+            $error = true;
+        }
+
+        if ($error === false) {
+            return;
         }
 
         $fix = $phpcsFile->addFixableError(
@@ -97,7 +91,7 @@ public function process(File $phpcsFile, $stackPtr)
         );
 
         if ($fix === true) {
-            if ($tokens[$stackPtr]['code'] === \T_NAME_FULLY_QUALIFIED) {
+            if ($contentLC === '\true' || $contentLC === '\false' || $contentLC === '\null') {
                 // PHPCS 4.x.
                 $phpcsFile->fixer->replaceToken($stackPtr, \ltrim($tokens[$stackPtr]['content'], '\\'));
             } else {