[TASK] Add formal type parameter to ParserState::setCharset() (#958)

Author: JakeQZ

config/phpstan-baseline.neon

@@ -174,12 +174,6 @@ parameters:
 			count: 2
 			path: ../src/Parsing/ParserState.php
 
-		-
-			message: '#^Parameters should have "string" types as the only types passed to this method$#'
-			identifier: typePerfect.narrowPublicClassMethodParamType
-			count: 1
-			path: ../src/Parsing/ParserState.php
-
 		-
 			message: '#^Parameters should have "string\|int\|null" types as the only types passed to this method$#'
 			identifier: typePerfect.narrowPublicClassMethodParamType

src/Parsing/ParserState.php

@@ -68,10 +68,8 @@ public function __construct($text, Settings $parserSettings, $lineNumber = 1)
 
     /**
      * Sets the charset to be used if the CSS does not contain an `@charset` declaration.
-     *
-     * @param string $charset
      */
-    public function setCharset($charset): void
+    public function setCharset(string $charset): void
     {
         $this->charset = $charset;
         $this->characters = $this->strsplit($this->text);