separate commands into their own code blocks on Adding TypeScript page of Create React App docs

[hirehamir]

Is your proposal related to a problem?

When copying and pasting the command to add TypeScript to either an existing Create React App project or a new one, the clipboard receives both commands and # or, instead of the desired individual command.

Screen.Recording.2021-02-15.at.9.29.18.AM.mov

Describe the solution you'd like

We can separate each command into its own code block for easier copying and pasting. I've created a fix for this in #10553. #10553 closes this if we decide to merge it.

Describe alternatives you've considered

I think this is the approach that makes things easiest for people just wanting to copy the commands.

Additional context

The page that this issue and the pull request I have open for it refers to is https://create-react-app.dev/docs/adding-typescript/.

[hirehamir]

@mubarakn fixed this with #11757.