[Hyperdrive] Fix code block language (cloudflare#25186)

Author: pedrosousa

src/content/docs/hyperdrive/examples/connect-to-postgres/postgres-drivers-and-libraries/prisma-orm.mdx

@@ -75,7 +75,7 @@ model User {
 
 Add your database connection string to the `.env` file created by Prisma:
 
-```env title=".env"
+```txt title=".env"
 DATABASE_URL="postgres://user:password@host:port/database"
 ```