[Pages] Added limitation for custom domains (#938)

* Adde limitation on custom domains

Added new item that explains it's currently not possible to add custom domains with wildcard in it, e.g. *.domain.com. This is something that's currently blocking me from migrating over to Pages, so it could be helpful information to others who are planning to migrate.

* Update products/pages/src/content/platform/known-issues.md

* Update products/pages/src/content/platform/known-issues.md

Co-authored-by: Kate Tungusova <[email protected]>

Author: raRaRa

products/pages/src/content/platform/known-issues.md

@@ -8,5 +8,6 @@ Here are some known bugs and issues that we're aware of with Cloudflare Pages:
 - Hugo builds automatically run an old version. To run the latest version of Hugo (for instance, 0.80.0), you'll need to set an environment variable. Set `HUGO_VERSION` to `0.80.0` or the Hugo version of your choice.
 - By default, we use Node 10 in the Pages build environment. If you need to use a newer Node version, see our [Build configuration page](https://developers.cloudflare.com/pages/platform/build-configuration) for configuration options.
 - For users migrating from Netifly, Cloudflare does not support Netlify's Forms and Serverless Functions features. Cloudflare Pages does not directly support HTTP header customization, but it can be done through Workers. Refer to the ["Add custom HTTP headers"](/how-to/add-custom-http-headers) guide for more information.
+- It is currently not possible to add a custom domain with a wildcard, e.g. *.domain.com.
 
-Having an issue that you don't see listed above? Let us know in the Cloudflare Workers Discord. Get your invite at [discord.gg/cloudflaredev](https://discord.gg/cloudflaredev), and share your bug report in the #pages-help channel.
+If you have an issue that you do not see listed, let the team know in the Cloudflare Workers Discord. Get your invite at [discord.gg/cloudflaredev](https://discord.gg/cloudflaredev), and share your bug report in the #pages channel.