[Documentation] Minor improvements of the Vite installation guide

[molefrog]

First of all, Reshaped looks sick! Absolutely love its design and simplicity.

I've followed the Vite guide from the docs and there were some minor things I thought would be nice to have in the guide. It wasn't a big deal, but it could save up a couple of minutes for people who aren't familiar with Vite.

1. It seems like Vite does not generate postcss.config.js by default, while the docs assume the file is already there.
2. The code for App.tsx doesn't contain a default export so a simple copy-and-paste won't work. Adding an extra line to that snippet could slightly improve the experience.

[blvdmitry]

Thanks for highlighting these, I'll update those bits in the Vite docs for the upcoming release 🙌

[blvdmitry]

Updated the content in the upcoming release planned for the next Monday