migrate sveltekit-3: comments in tsconfig.json are removed #1367

In sv@1.0.1, the sveltekit-3 migration rewrites tsconfig.json and removes all comments, even though the file allows them (JSONC).

Before:

"lib": ["ES2023", "DOM"], // sync with app.html browser check
"types": ["node"],

// Stricter Typechecking Options
"noUncheckedIndexedAccess": true,

After:

"lib": [
	"ES2023",
	"DOM"
],
"types": [
	"node",
	"$app/types"
],
"noUncheckedIndexedAccess": true,

Expected: Edit tsconfig.json in a way that keeps existing comments and blank lines.