feat(fonts): export googleicons provider (withastro#13035)

Co-authored-by: Chris Swithinbank <[email protected]>

Author: florian-lefebvre

src/content/docs/en/reference/experimental-flags/fonts.mdx

@@ -161,6 +161,7 @@ The following providers have built-in support:
 - [Fontshare](https://www.fontshare.com/)
 - [Fontsource](https://fontsource.org/)
 - [Google](https://fonts.google.com/)
+- [Google Icons](https://fonts.google.com/icons)
 
 To use a built-in remote provider, configure `provider` with the appropriate value for your chosen font provider:
 
@@ -218,6 +219,28 @@ provider: fontProviders.google({
 
 </TabItem>
 
+<TabItem label="Google Icons">
+
+<p>
+<Since v="5.16.9" />
+</p>
+
+```js
+provider: fontProviders.googleicons()
+```
+
+Additionally, the `googleicons()` font provider accepts all options available for the [unifont Google Icons options](https://github.com/unjs/unifont/#options-2):
+
+```js
+provider: fontProviders.googleicons({
+	glyphs: {
+		"Material Symbols Outlined": ["arrow_right", "favorite", "arrow_drop_down"]
+	}
+})
+```
+
+</TabItem>
+
 </Tabs>
 
 ## Usage examples