Update robots.txt with Content Signals - https://contentsignals.org/

Author: maartenba

astro/public/robots.txt

@@ -1,4 +1,5 @@
 User-agent: *
+Content-Signal: ai-train=yes, search=yes, ai-input=yes
 Allow: /
 
-Sitemap: https://docs.duendesoftware.com/sitemap-index.xml
+Sitemap: https://docs.duendesoftware.com/sitemap-index.xml