docs(zh): updated api docs 950763f...a0b40f0

[Jinjiang]

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

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

Ref: 950763f...a0b40f0
/cc @Justineo

[maicss]

两位大佬，需要帮忙吗，我看你们一次翻译这么多……
如果不需要的话，能不能帮我一哈？
#1566

[Jinjiang]

@maicss 多谢。我们确实需要更多人参与到翻译工作中来。我们目前的维护方式是把最后一次翻译时 dev 分支的 commit hash 记录下来，然后用这个 hash 定期比较最新的 dev 分支。当发现 docs 目录变化比较可观的时候做一次翻译同步，类似这个 PR。同样的方式也会用在 vuex, vue-router, vue-loader 等别的仓库，也包括中文官网。
VTU 前段时间确实疏于同步了，而且在 1.0 之前琐碎的改动比较多，所以这次的翻译量比较大。

(translation: for short it's talking about how to contribute Chinese docs translation, not about the content in this PR.)