Add run as admin suggestion for Windows

[HotaruBlaze]

If you are running Discord as administrator, NSO-RPC will fail to connect to the discord IPC pipe due to windows permissions.

I attempted to catch the '[WinError 5] Access is denied' exception at client/cli.py#L50-L56, as it returns an IOError exception, however I had multiple timing and scope(?) issues around that, even trying to add handler and extra stuff around a simple boolean had consistency issues, reporting not connected to discord, then afterwards saying we are fine etc.

This solution's main issue is that its assuming on windows, the only reason for NSO-RPC to have issues connecting to discord is because Discord is running with Admin privileges.

Note: This will give a false positive telling the user to try running NSO-RPC with Admin if Discord is not running.

[HotaruBlaze]

Forgot to add the preview of the change, when its unable to connect to discord.

[MCMi460]

I made some changes upstream that should solve those false positives (instead editing the message to display the actual error under those circumstances). Thank you for noticing this and working to fix it so quickly!