docs(name): Add link to deprecation explanation

[travis5491811]

Closes #1745

Add reference to doc to explain to users why name is deprecated and what they should do next!

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe: Doc update

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the dev branch.
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• All tests are passing: https://github.com/vuejs/vue-test-utils/blob/dev/.github/CONTRIBUTING.md#development-setup
• New/updated tests are included

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information:
Just updating docs so new users don't abandon this project. This should also address #1745

[afontcu]

Hi! Thank you for this.

Looks like the link is not rendered as a link (because it is a markdown file):

Do you think you could update the PR to create a markdown link? [link text](url to link)

[travis5491811]

Hi! Thank you for this.

Looks like the link is not rendered as a link (because it is a markdown file):

Do you think you could update the PR to create a markdown link? [link text](url to link)

No problem. pull request updated.

[afontcu]

Thanks!