Missing decpration warning for wrapper.contains() from documentaion

[SmilingJoe]

What problem does this feature solve?

Recently upgraded @vue/test-utils from 1.0.0-beta.31 to 1.0.2. Upon running our unit tests, received the following error:
ERROR: '[vue-test-utils]: contains is deprecated and will be removed in the next major version Use wrapper.find, wrapper.findComponent or wrapper.get instead'

Noticed that there is no warning of this deprecation specified in the API Wrapper documentation:
https://vue-test-utils.vuejs.org/api/wrapper/#contains

Providing this deprecation warning, along with a specific replacement example, in the documentation will save time for developers.

What does the proposed API look like?

Propose adding the following deprecation warning to the top of relevant API Wrapper "contains" document:

| Deprecation warning
| `contains` is deprecated and will be removed in future releases. Use 'wrapper.find', `wrapper.findComponent` or `wrapper.get` instead.

[SmilingJoe]

Just noticed that there is a deprecation warning on the 'wrapper.find' document (https://vue-test-utils.vuejs.org/api/wrapper/#find), which would obviously preclude that method from being part of this deprecation warning.

[afontcu]

Hi! You're right, we're missing a deprecation warning on docs. Fancy to open up a PR? :)

[SmilingJoe]

Sure, I can do that.

[afontcu]

Hi @SmilingJoe! Did you have the chance to take a look at this? :)

[SmilingJoe]

Sorry @afontcu I've been tied up with other projects. Looking into this now as I have some free time.

Raised PR: #1612

[afontcu]

Fixed in #1612!