Create shading.md

Author: rasamassen

docs/usage/styles/shading.md

@@ -0,0 +1,28 @@
+# Shading Styles
+
+``` php
+<?php
+
+use PhpOffice\PhpWord\Style\Shading;
+$phpWord->addParagraphStyle('pStyle', ['shading' => ['pattern' => Shading::PATTERN_SOLID, 'fill' => FF0000]]);
+$section->addText('Hello, World!', null, 'pStyle');
+
+```
+
+## Constants
+- `PATTERN_CLEAR`. No pattern.
+- `PATTERN_SOLID`. 100% fill pattern.
+- `PATTERN_HSTRIPE`. Horizontal stripe pattern.
+- `PATTERN_VSTRIPE`. Vertical stripe pattern.
+- `PATTERN_DSTRIPE`. Diagonal stripe pattern.
+- `PATTERN_HCROSS`. Horizontal cross pattern.
+- `PATTERN_DCROSS`. Diagonal cross pattern.
+
+## Options
+- `color`. Shading pattern color, e.g. *FF0000*.
+- `fill`. Shading background color, e.g. *FF0000*.
+- `pattern`. Shading pattern.
+   * See constants above for possible values.
+
+## Used In
+- [`Style > Paragraph`](../styles/paragraph.md).