Resolve #949 (#968)
Resolve #949 (#968)

* docs(api): add provider/inject API example comments

ref: https://github.com/vuejs/vuejs.org/commit/025114990599e312f84eae7906328191503ba6fe

* docs(api): translate provide/inject API example comments

closes #949

potato4d/jp.vuejs.org,potato4d/jp.vuejs.org,vuejs/jp.vuejs.org,vuejs/jp.vuejs.org