[ci skip] SomeUnique example duplicate removed (#6145)

docs/docs/models-definition.md

@@ -34,7 +34,6 @@ var Foo = sequelize.define('foo', {
  // Creating two objects with the same value will throw an error. The unique property can be either a
  // boolean, or a string. If you provide the same string for multiple columns, they will form a
  // composite unique key.
- someUnique: {type: Sequelize.STRING, unique: true},
  uniqueOne: { type: Sequelize.STRING,  unique: 'compositeIndex'},
  uniqueTwo: { type: Sequelize.INTEGER, unique: 'compositeIndex'}