fix: favicon instructions

Author: TurtIeSocks

Diff for: server/src/configs/multi-domain-example/README.md

@@ -70,4 +70,5 @@ pm2 start ecosystem.config.js
 - Be sure to view the `nginx` file to see how to set up the reverse proxy for the different domains
 - The domains do not have to be subdomains of each other, they can be whatever you want, they are just used to differentitate the different configs
 - The `NODE_CONFIG_ENV` var names should not contain `/` or `.`
-- The `NODE_CONFIG_ENV` value does not have to be related to the domain its representing. The URL for the map could be `https://www.my-super-map.com` and the `NODE_CONFIG_ENV` could be `applemap` or `orangemap` or `bananamap` or whatever you want, as long as you point the nginx reverse proxy to the correct instance of the app
+- The `NODE_CONFIG_ENV` value does not have to be related to the domain its representing. The URL for the map could be `https://www.my-super-map.com` and the `NODE_CONFIG_ENV` could be `applemap` or `orangemap` or `bananamap` or whatever you want, as long as you point the nginx reverse proxy to the correct instance of the app
+- Custom favicons can be set by putting the respective `{NODE_CONFIG_ENV}.ico` in the `public/favicon` folder