[CLEANUP] Extract method Color::shouldRenderAsHex (#853)

Resolves #852.

Author: JakeQZ

src/Value/Color.php

@@ -224,12 +224,7 @@ public function __toString(): string
 
     public function render(OutputFormat $outputFormat): string
     {
-        // Shorthand RGB color values
-        if (
-            $outputFormat->getRGBHashNotation()
-            && $this->getRealName() === 'rgb'
-            && $this->allComponentsAreNumbers()
-        ) {
+        if ($this->shouldRenderAsHex($outputFormat)) {
             return $this->renderAsHex();
         }
 
@@ -240,6 +235,14 @@ public function render(OutputFormat $outputFormat): string
         return parent::render($outputFormat);
     }
 
+    private function shouldRenderAsHex(OutputFormat $outputFormat): bool
+    {
+        return
+            $outputFormat->getRGBHashNotation()
+            && $this->getRealName() === 'rgb'
+            && $this->allComponentsAreNumbers();
+    }
+
     /**
      * The function name is a concatenation of the array keys of the components, which is passed to the constructor.
      * However, this can be changed by calling {@see CSSFunction::setName},