Astro wizard mangling files

I used the wizard on an Astro project, and it's managed to rewrite while cutting off the `---` at the top of several files. Left me very confused why things were failing. And leaving me to undo a bunch of code.

In general, I'd love a non-destructive option because I just wanted to put the code in my own layout. I didn't think it'd do a whole extra 'layout' for a small piece of code.

