📝 Update docs for broken demo (#421)

Relates to #420

docs/pages/installation/getting-started.mdx

@@ -2,21 +2,18 @@ import { Callout } from 'nextra-theme-docs'
 
 # Getting Started
 
+## Demo
+
 <Callout emoji="🚧">
-	This documentation is under active development. Please keep that in mind while using this guide
-	and feel free to [open an issue]( https://github.com/stumpapp/stump/issues/new/choose) if you
-	encounter any problems or inconsistencies
+	The demo is currently unavailable. I will try to get it back up as soon as possible. See the
+	relevant [issue](https://github.com/stumpapp/stump/issues/420).
 </Callout>
 
-## Demo
-
 A demo can be found at [demo.stumpapp.dev](https://demo.stumpapp.dev). The login credentials are:
 
 - **Username:** `demouser`
 - **Password:** `demouser10801`
 
-I try to keep the demo up to date, but it may not always be the case.
-
 ## Installation methods
 
 There are three ways to install Stump: