docs(cn): translate content/warnings/unknown-prop.md into Chinese (#111)

https://stackblitz.com/edit/react-unknown-prop
无法重现这个 warning 可能是我例子写得不够高级…

Author: seognil

content/warnings/unknown-prop.md

@@ -1,39 +1,39 @@
 ---
-title: Unknown Prop Warning
+title: 警告：未知的 Prop
 layout: single
 permalink: warnings/unknown-prop.html
 ---
-The unknown-prop warning will fire if you attempt to render a DOM element with a prop that is not recognized by React as a legal DOM attribute/property. You should ensure that your DOM elements do not have spurious props floating around.
+当你尝试用一个无法被 React 识别为合法 DOM 属性（attribute / property）的 prop 渲染 DOM 元素时，会出现 unknown-prop 警告。你应该确保你的 DOM 元素上没有这类失效的 props。
 
-There are a couple of likely reasons this warning could be appearing:
+这个警告出现的原因可能有如下几种：
 
-1. Are you using `{...this.props}` or `cloneElement(element, this.props)`? Your component is transferring its own props directly to a child element (eg. [transferring props](/docs/transferring-props.html)). When transferring props to a child component, you should ensure that you are not accidentally forwarding props that were intended to be interpreted by the parent component.
+1. 你使用了 `{...this.props}` 或者 `cloneElement(element, this.props)` 吗？你的组件会直接把它自己的 props 传递给子元素（例如 [传递 props](/docs/transferring-props.html))。向子组件传递 props 时，你应该避免转发本应由父组件解释的 props。
 
-2. You are using a non-standard DOM attribute on a native DOM node, perhaps to represent custom data. If you are trying to attach custom data to a standard DOM element, consider using a custom data attribute as described [on MDN](https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Using_data_attributes).
+2. 你在原生 DOM 节点上使用的是非标准的 DOM 属性，或许是用来表示自定义数据。如果你想把自定义数据附加到标准 DOM 元素上，请参考 [MDN](https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Using_data_attributes) 使用自定义的 data 属性。
 
-3. React does not yet recognize the attribute you specified. This will likely be fixed in a future version of React. However, React currently strips all unknown attributes, so specifying them in your React app will not cause them to be rendered.
+3. React 还不能识别你指定的属性。这可能会在 React 的未来版本中修复。不过，React 目前会去除所有未知的属性，因此即使在 React 应用中指定这些属性也无法使它们渲染。
 
-4. You are using a React component without an upper case. React interprets it as a DOM tag because [React JSX transform uses the upper vs. lower case convention to distinguish between user-defined components and DOM tags](/docs/jsx-in-depth.html#user-defined-components-must-be-capitalized).
+4. 你在使用 React 组件但是没有使用大写，React 会将其解释为 DOM 标签，这是因为 [React JSX 语法使用大小写约定来区分用户自定义组件和 DOM 标签](/docs/jsx-in-depth.html#user-defined-components-must-be-capitalized)。
 
 ---
 
-To fix this, composite components should "consume" any prop that is intended for the composite component and not intended for the child component. Example:
+要解决这个问题，组合组件应该“消费掉”任何只用于复合组件而不是子组件的 prop。例如：
 
-**Bad:** Unexpected `layout` prop is forwarded to the `div` tag.
+**Bad：** `layout` prop 意外转发给了 `div` 标签。
 
 ```js
 function MyDiv(props) {
   if (props.layout === 'horizontal') {
-    // BAD! Because you know for sure "layout" is not a prop that <div> understands.
+    // 糟糕的！ 因为你很清楚 <div> 不知道如何处理 "layout" 这个 prop。
     return <div {...props} style={getHorizontalStyle()} />
   } else {
-    // BAD! Because you know for sure "layout" is not a prop that <div> understands.
+    // 糟糕的！ 因为你很清楚 <div> 不知道如何处理 "layout" 这个 prop。
     return <div {...props} style={getVerticalStyle()} />
   }
 }
 ```
 
-**Good:** The spread operator can be used to pull variables off props, and put the remaining props into a variable.
+**Good：** 展开运算符能从 props 中剥离变量，并将剩余的 props 放到一个新变量中。
 
 ```js
 function MyDiv(props) {
@@ -46,7 +46,7 @@ function MyDiv(props) {
 }
 ```
 
-**Good:** You can also assign the props to a new object and delete the keys that you're using from the new object. Be sure not to delete the props from the original `this.props` object, since that object should be considered immutable.
+**Good：** 你也可以将 props 分配给一个新的对象，并从新对象中删除你正在使用的属性。注意不要删除原始对象 `this.props` 中的 props，因为这个对象理应被认为是不可变的。
 
 ```js
 function MyDiv(props) {