fix(docs):added missing imports in examples

[guzuro]

Description

There is some places in docs where examples in playground cant be run because of missing imports, like 'ref' or composables from 'vuestic-ui'. Looked through all the places and added necessary imports

Markup:

import { * } from 'vue'; 
import { * } from 'vuestic-ui';

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any feature but make things better)

[m0ksem]

Thanks!