[BUGFIX] Correct DocBlock for ParserState::consumeUntil() (#1338)

The special `EOF` constant is actually defined as `null`, so the stop
characters may be strings or `null`.

Author: JakeQZ

config/phpstan-baseline.neon

@@ -18,12 +18,6 @@ parameters:
 			count: 1
 			path: ../src/CSSList/Document.php
 
-		-
-			message: '#^Call to function in_array\(\) with arguments null, list\<string\> and true will always evaluate to false\.$#'
-			identifier: function.impossibleType
-			count: 1
-			path: ../src/Parsing/ParserState.php
-
 		-
 			message: '#^Negated boolean expression is always true\.$#'
 			identifier: booleanNot.alwaysTrue

src/Parsing/ParserState.php

@@ -328,7 +328,7 @@ public function isEnd(): bool
     }
 
     /**
-     * @param list<string>|string $stopCharacters
+     * @param list<string|self::EOF>|string|self::EOF $stopCharacters
      * @param array<int, Comment> $comments
      *
      * @throws UnexpectedEOFException