Sync with reactjs.org @ 87dcdbed

[reactjs-translation-bot]

This PR was automatically generated.

Merge changes from reactjs.org at 87dcdbed

The following files have conflicts and may need new translations:

• [ ] src/site-constants.js
  • [ ] src/components/MarkdownPage/MarkdownPage.js
  • [ ] content/home/marketing/learn-once-write-anywhere.md
  • [ ] content/docs/state-and-lifecycle.md
  • [ ] content/docs/rendering-elements.md
  • [ ] content/docs/lists-and-keys.md
  • [ ] content/docs/lifting-state-up.md
  • [ ] content/docs/introducing-jsx.md
  • [ ] content/docs/handling-events.md
  • [ ] content/docs/getting-started.md
  • [ ] content/docs/forms.md
  • [ ] content/docs/create-a-new-react-app.md
  • [ ] content/docs/conditional-rendering.md
  • [ ] content/docs/components-and-props.md

Please fix the conflicts by pushing new commits to this pull request, either by editing the files directly on GitHub or by checking out this branch.

DO NOT SQUASH MERGE THIS PULL REQUEST!

Doing so will "erase" the commits from master and cause them to show up as conflicts the next time we merge.

[netlify[bot]]

Deploy preview for hy-reactjs failed.

Built with commit 079754d75bba5d768e71d6a7acb897ebc940655d

https://app.netlify.com/sites/hy-reactjs/deploys/5f3a9c75b569820007d4babb