Add static assets to docs pages (#6951)

## Summary

This PR points the docs towards the static assets that we use for
`astral.sh`, so that we can use shared assets for the Ruff and uv docs.

docs/.overrides/main.html

@@ -0,0 +1,20 @@
+{% extends "base.html" %}
+
+{% block extrahead %}
+<link rel="apple-touch-icon" sizes="180x180" href="/static/apple-touch-icon.png"/>
+<link rel="icon" type="image/png" sizes="32x32" href="/static/favicon-32x32.png"/>
+<link rel="icon" type="image/png" sizes="16x16" href="/static/favicon-16x16.png"/>
+<link rel="manifest" href="/static/site.webmanifest"/>
+<link rel="mask-icon" href="/static/safari-pinned-tab.svg" color="#2e183d"/>
+<meta name="msapplication-TileColor" content="#d7ff64"/>
+<meta name="theme-color" content="#ffffff"/>
+<meta name="robots" content="index,follow"/>
+<script type="application/ld+json">
+    {
+        "@context": "https://schema.org",
+        "@type": "WebSite",
+        "name": "Astral",
+        "url": "https://astral.sh"
+    }
+</script>
+{% endblock %}

mkdocs.template.yml

@@ -2,7 +2,7 @@ site_name: uv
 theme:
   name: material
   logo: assets/logo-letter.svg
-  favicon: assets/favicon.svg
+  favicon: assets/favicon.ico
   features:
     - navigation.instant
     - navigation.instant.prefetch