Add admin warnings to INSTALLING.md (#561)

docs/1_INSTALLING.md

@@ -31,12 +31,14 @@ Welcome to Megu's Installation Guide! In this file, you will learn about how to
 
 Install `pnpm`:
 
-> :exclamation: this may need to be run as admin depending on your system, and you may need to close and reopen your terminal.
+> :exclamation: This next command may need to be run as admin/sudo depending on your system, and you may need to close and reopen your terminal for pnpm to be in your PATH.
 
 ```shell
 npm i -g pnpm
 ```
 
+> :exclamation: **IMPORTANT** Make sure you aren't using an admin/sudo terminal from here onwards. It **will** mess up your Discord/Vencord instance and you **will** most likely have to reinstall.
+
 Clone Vencord:
 
 ```shell