README: error in setting.json example

[phenomen]

Single quotes are invalid in json.

https://github.com/sveltejs/prettier-plugin-svelte/blob/f86171d1eddcac3598a9ea57e2182053c9e739dd/README.md?plain=1#L260C6-L260C6

Should be:

// settings.json
{
    // ..
    "prettier.documentSelectors": ["**/*.svelte"]
}