Environment variable syntax

[PeterTrotter]

Having changed the Caddyfile to use environment vars from:

something.blah.ts.net {
	handle_path /hello {
		reverse_proxy hello:8080
	}
}

to

{$TAILSCALE_HOSTNAME} {
	handle_path /hello {
		reverse_proxy hello:8080
	}
}

Caddy is happy but we get an error raised by the plugin CaddyTokenType.COMMENT or CaddyTokenType.EOL expected, got '}':

Thanks for a very helpful plugin.