Fix Korean language code in an example

Author: domenic

README.md

@@ -334,7 +334,7 @@ const session = await ai.languageModel.create({
  prefer speaking in Japanese, and return to the Japanese conversation once any sidebars are
  concluded.
  `,
- expectedInputLanguages: ["en" /* for the system prompt */, "ja", "kr"]
+ expectedInputLanguages: ["en" /* for the system prompt */, "ja", "ko"]
 });
 ```