[CLEANUP] Avoid magic method forwarding in AtRuleSet (#1153)

Part of #1147

Author: oliverklee

config/phpstan-baseline.neon

@@ -126,18 +126,6 @@ parameters:
 			count: 1
 			path: ../src/Rule/Rule.php
 
-		-
-			message: '#^Call to an undefined method Sabberworm\\CSS\\OutputFormat\:\:comments\(\)\.$#'
-			identifier: method.notFound
-			count: 1
-			path: ../src/RuleSet/AtRuleSet.php
-
-		-
-			message: '#^Call to an undefined method Sabberworm\\CSS\\OutputFormat\:\:spaceBeforeOpeningBrace\(\)\.$#'
-			identifier: method.notFound
-			count: 1
-			path: ../src/RuleSet/AtRuleSet.php
-
 		-
 			message: '#^Only booleans are allowed in an if condition, string given\.$#'
 			identifier: if.condNotBoolean

src/RuleSet/AtRuleSet.php

@@ -63,12 +63,13 @@ public function __toString(): string
 
     public function render(OutputFormat $outputFormat): string
     {
-        $result = $outputFormat->comments($this);
+        $formatter = $outputFormat->getFormatter();
+        $result = $formatter->comments($this);
         $arguments = $this->arguments;
         if ($arguments) {
             $arguments = ' ' . $arguments;
         }
-        $result .= "@{$this->type}$arguments{$outputFormat->spaceBeforeOpeningBrace()}{";
+        $result .= "@{$this->type}$arguments{$formatter->spaceBeforeOpeningBrace()}{";
         $result .= $this->renderRules($outputFormat);
         $result .= '}';
         return $result;