`vi` as alias of `vitest`

import { vi } from 'vitest'
vi.fn()
vi.mock()

Reads like vi-test, vi-fn, vi-mock

We are going to use the vi.fn() form in the docs, and mention that vitest is an alias in case users prefer the more explicit vitest.fn()

[antfu]

https://github.com/antfu-sponsors/vitest/pull/163 implemented it and shipped in v91

[patak-dev]

@Shinigami92 is this a positive or negative response to the issue? 😅