docs(aliasing): update import code

[santiagoaloi]

Description

A minor tweak in the importing of components in devresulting in slight performance benefit.
This only affects dev mode as in prod threeshaking will automatically optimize these kind of imports.

from:

import { VBtn } from 'vuetify/components'

to:

import { VBtn } from 'vuetify/components/VBtn'

[johnleider]

small tweak, otherwise lgtm