feat(transfer): add renderCustom props

[jasonslyvia]

First of all, thanks for your contribution! :-)

Please makes sure these boxes are checked before submitting your PR, thank you!

• Make sure you follow antd's code convention.
• Run npm run lint and fix those errors before submitting in order to keep consistent code style.
• Rebase before creating a PR to keep commit history clear.
• Add some descriptions and refer relative issues for you PR.

---

Add custom render support for Transfer component, for implementing features like this:

When you want to render custom element in Transfer while still have the filter support, you can pass both render and renderCustom props.

• render will be used when rendering title or matching filters
• renderCustom will be used for rendering the transfer item

I believe this change is backward-compatible.

[mention-bot]

By analyzing the blame information on this pull request, we identified @waywardmonkeys, @afc163 and @benjycui to be potential reviewers

[afc163]

Maybe this will be better:

// return item.content should be backward-compatible.
render(item) {
  return {
    label: <div className="custom-item" style={{ color: 'red' }}>{item.content} - {item.description}</div>,   // for displayed item
    value: item.content,   // for title and filter matching
  };
}

[jasonslyvia]

I'm okay with either way but it's up to you, so I've updated the PR, thoughts? @afc163

[afc163]

typeof <div></div> will be object too.

https://github.com/react-component/table/blob/0143748355fd07d056db201affb0594112ff6c93/src/TableRow.jsx#L26

[jasonslyvia]

Oops, missed that, a more solid check added.

[afc163]

rebase 一下，回头放到 1.1 上。

[jasonslyvia]

done

[jasonslyvia]

Please inform me of when you're ready to merge and I will rebase upstream one more time :P

[superRaytin]

Sorry for being late, please rebase and I will merge this PR

[jasonslyvia]

done

[superRaytin]

👍 👍

[afc163]

对，文档要对应更新下。

[superRaytin]

感觉增加一个 demo 就好了