[UX] Split README's install code block into 3

[willingc]

• Broke up the large code block into 3 blocks so that copy paste icon works

Howdy Astral friends! This is a small PR which is a small user experience improvement for smooth installs.

[zanieb]

Won't the copy paste fail because of the leading $ anyway?

[zanieb]

For some more context, in #5397 we made it so that the $ is stripped from copied console commands in the documentation but that doesn't apply to the README. I think we'll need to move the comments and $ out of the code blocks to achieve the desired effect here.

Nice to see you Carol! Thanks for taking the time to contribute :)

[willingc]

I'm not sure about the $. But I figured that I would mention it since the copy paste grabbed all of lines and made the shell grumpy. Good to see you virtually too.

[zanieb]

I gave it a try in the preview and we'll need to change that before we can merge. I can futz with it sometime soon if you don't want to.

[willingc]

It does fail if you keep the preceding $. I've removed the $ and switched the syntax highlighting to bash. I'm able to copy-paste fine on Mac. YMMV on Windows (I don't have a good test machine for that.) @zanieb

[zanieb]

Thank you!