Feedback: Modify Codeblock examples to clarify changes made

[ANeaves]

Codeblocks currently do not make it anywhere near obvious enough what changes are being made, where they are changing, what file they modify, or in some cases WHY they are being changed

Try using the DIFF syntax for the code blocks to highlight these changes in red/green.

Do not shorten parts of the code thought ignorable using the ellipsis, as that also causes issues.

[ANeaves]

Additional Notes:
SOme typos/unupdated sections in the codeblocks mean they dont always match the actual sourcecode (see: Function App() vs const App = () =>)

Some filename specifications at the top of the codeblocks are incorrect vs the actual filename (App.tsx vs app.tsx). It may also be worth providing a more full path as the name rather than just the file itself (react/src/App.tsx)

[ANeaves]

More Notes:

Use individual lines for cut/paste items, such as the command line parts