doc: update ORM syntax

doc/docs.md

@@ -1470,27 +1470,27 @@ struct Customer { // struct name has to be the same as the table name (for now)
     country string
 }
 
-db := pg.connect(db_name, db_user)
+db := sqlite.connect('customers.db')
 
 // select count(*) from Customer
-nr_customers := db.select count from Customer
+nr_customers := sql db { select count from Customer }
 println('number of all customers: $nr_customers')
 
 // V syntax can be used to build queries
 // db.select returns an array
-uk_customers := db.select from Customer where country == 'uk' && nr_orders > 0
+uk_customers := sql db { select from Customer where country == 'uk' && nr_orders > 0 }
 println(uk_customers.len)
 for customer in uk_customers {
     println('$customer.id - $customer.name')
 }
 
 // by adding `limit 1` we tell V that there will be only one object
-customer := db.select from Customer where id == 1 limit 1
+customer := sql db { select from Customer where id == 1 limit 1 }
 println('$customer.id - $customer.name')
 
 // insert a new customer
 new_customer := Customer{name: 'Bob', nr_orders: 10}
-db.insert(new_customer)
+sql db { insert new_customer into Customer }
 ```
 
 ## vfmt