Update the sign in docs to contain more precise information. (#71698)

* Update sign-in-to-grafana.md

* updates link

---------

Co-authored-by: Chris Moyer <chris.moyer@grafana.com>

docs/sources/setup-grafana/sign-in-to-grafana.md

@@ -20,9 +20,9 @@ This topic describes how to sign in to Grafana.
 
 To sign in to Grafana for the first time, follow these steps:
 
-1. Open your web browser and go to http://localhost:3000/.
+1. Open your web browser and go to root URL specified in [Grafana configuration file]({{< relref "./configure-grafana" >}}).
 
-   Unless you have configured a different port, Grafana listens to port `3000` by default.
+   Unless you have configured Grafana differently, it is set to use `http://localhost:3000` by default.
 
 1. On the signin page, enter `admin` for username and password.
 1. Click **Sign in**.