Remove unnecessary prefixes from CLI docs

[LostXOR]

The CLI docs have $ and ./ prefixes before each command. This is confusing, as the $ is not a part of the command at all and the ./ is Unix-specific.

This PR removes the prefixes from the commands, and adds a note at the beginning explaining that the ./ prefix should be added for MacOS/Linux users.

[Tyrrrz]

./ is also required on Windows with PowerShell if I remember correctly. Can you check?

[LostXOR]

I'm not sure, but the docs specify to use Command Prompt, and ./ doesn't work with it.

After extracting the .zip, open Command Prompt, aka cmd (Terminal on macOS and Linux).

[CharithBhat]

Tried it on Windows Powershell. ./ is required.
But with Command Prompt. I have to remove the ./ for it to work.

[Tyrrrz]

So it seems that all shells except Command Prompt require the ./, while Command Prompt doesn't work with ./. It's annoying. Maybe it's better to keep the ./ in docs and just add a note for Command Prompt users?

[LostXOR]

I guess that's probably best, I've updated the docs accordingly.