[CLEANUP] Add Color::getRealName method (#827)

The DocBlock should explain.

Co-authored-by: Jake Hotson <[email protected]>

Author: JakeQZ

src/Value/Color.php

@@ -227,7 +227,7 @@ public function render(OutputFormat $outputFormat): string
         // Shorthand RGB color values
         if (
             $outputFormat->getRGBHashNotation()
-            && \implode('', \array_keys($this->aComponents)) === 'rgb'
+            && $this->getRealName() === 'rgb'
             && $this->allComponentsAreNumbers()
         ) {
             $result = \sprintf(
@@ -242,6 +242,16 @@ public function render(OutputFormat $outputFormat): string
         return parent::render($outputFormat);
     }
 
+    /**
+     * 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},
+     * so is not reliable in situations where it's necessary to determine the function name based on the components.
+     */
+    private function getRealName(): string
+    {
+        return \implode('', \array_keys($this->aComponents));
+    }
+
     /**
      * Test whether all color components are absolute numbers (CSS type `number`), not percentages or anything else.
      * If any component is not an instance of `Size`, the method will also return `false`.