refactor: rename settings.kit to settings.svelte.kit

[ota-meshi]

This PR renames the settings in settings.kit to settings.svelte.kit.
There is no convention for the namespace under settings, but it's common for the community to use the name of the plugin.
I didn't notice that in the reviews 😓.

cc: @baseballyama
Sorry 😓. This also affects #283.

https://eslint.org/docs/latest/user-guide/configuring/configuration-files#adding-shared-settings

[changeset-bot]

⚠️ No Changeset found

Latest commit: 9deae87

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.