fix: use correct package name (#20021)

Author: Cherry

src/content/docs/kv/examples/workers-kv-to-serve-assets.mdx

@@ -49,7 +49,7 @@ cd example-kv-assets
 We'll also install the dependencies we will need for this project.
 
 ```sh
-npm install mimes accept-language-parser
+npm install mime accept-language-parser
 npm install --save-dev @types/accept-language-parser
 ```