FES ko new translation file + en file minor updates

[almchung]

This PR includes the Korean translation of FES error messages and minor updates to the English FES.

Changes:

• Added the FES Korean translation file (translations/ko/translation.json)
  • Translation credits: 염인화 (Inhwa Yeom), 전유진 (Youjin Jeon), 이지현 (Jihyun Lee), and 정앎 (Alm Chung).
• Started the FES Korean translation README/credits file (translations/ko/README.md)
• Minor design updates to the FES English translation file (translations/en/translation.json):
  1. Re-formatted error location information and move it to the beginning of a message
  2. Applied the "one external link per message" rule, condensing multiple URL links into one
  3. Standardized the different keys for web resources ({{url}}, {{url#}}, and {{link}}) into {{url}}
  4. Replaced emoji with Unicode symbols.
  5. Shortened messages.

This PR doesn't include the i18next Korean postposition plugin, which I may revisit after releasing the FES Korean translation.

After this contribution, the Korean FES i18n team wishes to share the internationalization process via our i18n guidelines/design notes and publish the materials somewhere on the p5js website, if possible. What would be the best way to discuss this?

Please let me know if you have any questions or concerns. Thank you!

PR Checklist

• npm run lint passes

[outofambit]

Thank you @almchung 염인화 (Inhwa Yeom), 전유진 (Youjin Jeon), and 이지현 (Jihyun Lee)!!

Could you open an issue in the p5 website repo to discuss adding your notes and materials to it? That sounds great to me :)