Sync with upstream @ 06979543

[javascript-translate-bot]

This PR was automatically generated.
Merge changes from en.javascript.info at 0697954

The following files have conflicts and may need new translations:

• README.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.

You can also close this PR and merge the changes manually:

1. git add remote upstream https://github.com/javascript-tutorial/en.javascript.info
2. Commit all current work and git checkout master
3. Pull from the English version git pull upstream master
4. Deal with the conflicts. If there are many changes in a file, e.g. README.md, then you could:
   • Checkout your version, git checkout --ours README.md
   • See what changed in the original file:
     • git diff --word-diff master...upstream/master README.md (three dots)
   • Update your version
   • git commit -m synced README.md
5. When conflicts resolved, git push origin master

P.S. Don't squash and merge if GitHub offers you, as this leads to same conflicts re-appear in the future.