add missing newline (#1941)

Author: fredr

docs/ts/primitives/cookies.mdx

@@ -104,7 +104,8 @@ export const get = api<Params, { msg: string }>(
     const lang = language?.value ?? "en";
     return { msg: `your language: ${lang}` };
   },
-);```
+);
+```
 
 ## Typed Cookie Values