Schema: Fix handling of arrays

[grigorischristainas]

I opened this pull request based on #883. It includes a refactoring regarding the array handling. Although the issue concerns arrays of objects, I think it makes sense to generalize it to all arrays.

Given the following example:

import type {Schema} from 'type-fest';

interface Users {
	names: Array<string>;
        fullnames: Array<{
		firstname: string;
		lastname: string;
	}>;
}

type UserMask = Schema<Users, 'mask' | 'hide' | 'show'>;

Previous implementation:

const userMaskSettings: UserMask = {
	names: 'mask',
        fullnames: 'mask'
}

New implementation:

const userMaskSettings: UserMask = {
	names: ['mask'],
	fullnames: [
		{
			firstname: 'show',
			lastname: 'hide'
		}
	]
}

I would be happy to make any further adjustments as needed.