mention hex colors

Author: freezy-sk

console/coloring.rst

@@ -40,13 +40,17 @@ It is possible to define your own styles using the
     use Symfony\Component\Console\Formatter\OutputFormatterStyle;
 
     // ...
-    $outputStyle = new OutputFormatterStyle('red', 'yellow', ['bold', 'blink']);
+    $outputStyle = new OutputFormatterStyle('#F00', 'yellow', ['bold', 'blink']);
     $output->getFormatter()->setStyle('fire', $outputStyle);
 
     $output->writeln('<fire>foo</>');
 
-Available foreground and background colors are: ``black``, ``red``, ``green``,
-``yellow``, ``blue``, ``magenta``, ``cyan`` and ``white``.
+Any hex color is supported for foreground and background colors. Besides that, these named colors are supported:
+``black``, ``red``, ``green``, ``yellow``, ``blue``, ``magenta``, ``cyan`` and ``white``.
+
+.. note::
+
+    If the terminal doesn't support true colors, the nearest named color is used.
 
 And available options are: ``bold``, ``underscore``, ``blink``, ``reverse``
 (enables the "reverse video" mode where the background and foreground colors