Install mise missing from docs

[rachelslurs]

Also, just to add on a step in the docs, a brew install mise or link to install docs would be helpful for people like myself who have never used mise before. 🤪

Also seeing:

mise ERROR no tasks defined in ~/blog. Are you in a project directory?
mise ERROR Run with --verbose or MISE_VERBOSE=1 for more information

Because again, I'm a mise newbie. Ended up figuring out I was supposed to add a mise.toml file to my project root, but I didn't see it in the examples (for my use case of Astro, here). I ended up figuring out what I should set my BUILD_KIT env variable from here too.

Also just came upon another piece of useful info that probably would be helpful to add to the README in the Astro example on static deployments here which ended up making me realize I didn't need to know any of the previous info .😅 I just merely needed to point the root directory to look in the right place.

Let me know if I'm completely off here though... otherwise I'd be happy to open a PR with some help on the docs by someone who is likely a big segment of your target audience I think.
Rachel