docs: update tailscale-serve.md (#221)

* docs: update tailscale-serve.md

* fix: move info to correct location

docs/installation/reverse-proxy/tailscale-serve.md

@@ -94,6 +94,10 @@ volumes:
   }
 ```
 
+  :::info
+  There is no need to set environment variable for `TS_CERT_DOMAIN`. It pulls that directly from your account.
+  :::
+
 2. **Generate a Tailscale auth key**
    - Go to the [Tailscale Admin Console](https://login.tailscale.com/admin/settings/keys)
    - Click on "Generate auth key"
@@ -170,4 +174,4 @@ Using Tailscale Serve as a reverse proxy for autobrr provides a secure and conve
 [^1]: Read more about Tailscale Serve in the official docs: https://tailscale.com/kb/1242/tailscale-serve
 [^2]: A Tailnet is your private network created by Tailscale, encompassing all your devices and users.
 [^3]: MagicDNS is a Tailscale feature that automatically gives DNS names to the devices on your network, making them easier to access.
-[^4]: Let's Encrypt is a free, automated, and open Certificate Authority providing trusted certificates for HTTPS encryption.
+[^4]: Let's Encrypt is a free, automated, and open Certificate Authority providing trusted certificates for HTTPS encryption.