Squiz/MemberVarSpacing: allow for PHP 8.1+ readonly properties

Readonly properties can be declared without visibility: https://3v4l.org/OS9hE
The sniff did not take this into account.

Fixed now.

Includes tests.

Author: jrfnl

src/Standards/Squiz/Sniffs/WhiteSpace/MemberVarSpacingSniff.php

@@ -47,6 +47,7 @@ protected function processMemberVar(File $phpcsFile, $stackPtr)
 
         $validPrefixes   = Tokens::$methodPrefixes;
         $validPrefixes[] = T_VAR;
+        $validPrefixes[] = T_READONLY;
 
         $startOfStatement = $phpcsFile->findPrevious($validPrefixes, ($stackPtr - 1), null, false, null, true);
         if ($startOfStatement === false) {

src/Standards/Squiz/Tests/WhiteSpace/MemberVarSpacingUnitTest.inc

@@ -372,3 +372,10 @@ enum SomeEnum
 
     case ONE = 'one';
 }
+
+class SupportReadonlyProperties {
+    readonly int $readonlyA;
+    public readonly string $publicReadonly;
+    readonly bool $readonlyB;
+    readonly private bool $readonlyPrivate;
+}

src/Standards/Squiz/Tests/WhiteSpace/MemberVarSpacingUnitTest.inc.fixed

@@ -357,3 +357,14 @@ enum SomeEnum
 
     case ONE = 'one';
 }
+
+class SupportReadonlyProperties {
+
+    readonly int $readonlyA;
+
+    public readonly string $publicReadonly;
+
+    readonly bool $readonlyB;
+
+    readonly private bool $readonlyPrivate;
+}

src/Standards/Squiz/Tests/WhiteSpace/MemberVarSpacingUnitTest.php

@@ -67,6 +67,10 @@ public function getErrorList()
             353 => 1,
             357 => 1,
             366 => 1,
+            377 => 1,
+            378 => 1,
+            379 => 1,
+            380 => 1,
         ];
 
     }//end getErrorList()