docs(sequelize): omitNull only works for CREATE/UPDATE queries

lib/sequelize.js

@@ -146,7 +146,7 @@ class Sequelize {
    * @param {boolean}  [options.standardConformingStrings=true] The PostgreSQL `standard_conforming_strings` session parameter. Set to `false` to not set the option. WARNING: Setting this to false may expose vulnerabilities and is not recommended!
    * @param {Function} [options.logging=console.log] A function that gets executed every time Sequelize would log something. Function may receive multiple parameters but only first one is printed by `console.log`. To print all values use `(...msg) => console.log(msg)`
    * @param {boolean}  [options.benchmark=false] Pass query execution time in milliseconds as second argument to logging function (options.logging).
-   * @param {boolean}  [options.omitNull=false] A flag that defines if null values should be passed to SQL queries or not.
+   * @param {boolean}  [options.omitNull=false] A flag that defines if null values should be passed as values to CREATE/UPDATE SQL queries or not.
    * @param {boolean}  [options.native=false] A flag that defines if native library shall be used or not. Currently only has an effect for postgres
    * @param {boolean}  [options.replication=false] Use read / write replication. To enable replication, pass an object, with two properties, read and write. Write should be an object (a single server for handling writes), and read an array of object (several servers to handle reads). Each read/write server can have the following properties: `host`, `port`, `username`, `password`, `database`
    * @param {object}   [options.pool] sequelize connection pool configuration