Update README.md

[codehooni]

There was one mistake I made in the contribution process. The Korean flag was not properly displayed in the README.md file. 🇰🇷 was incorrectly marked as :ko: Please change it again. I'm sorry for the inconvenience.

[goatshriek]

It is no trouble at all, thanks for submitting a fix.

I hadn't actually considered putting the code points directly into the README before, and I think this actually makes more sense than using the GitHub markdown name, which has confused myself and others before as well. I will probably move the README to do this at some point in the future.

For now to keep everything consistent, could you please update your change to use :kr: instead? This should render properly as 🇰🇷 .

[goatshriek]

If you'd like, I can also make the change of all flags to the direct unicode characters as part of #425, in which case you can simply close this pull request. Either way forward is fine with me.

[codehooni]

I think it would be nice if all the flags were changed to Unicode directly at once as part of #425 work, so I'll close that PR!