Removed leading $ from cli code blocks

[shinyzhu]

Summary

This fix would reduce typing when copying cli codes from the docs. Now you can just click the copy button then without any modify to paste to your cli.

For example, if the cli code comes with a $, when I copied it I need remove the leading $ in my cli.

The normal code blocks are not changed. :)

Hope this could improve the experience.

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.