docs(ngModelOptions): make object notation style consistent

There is a space before and after `{` and `}` for most of the objects throughout the docs.

Closes angular#11871

Author: stevemao

src/ng/directive/ngModel.js

@@ -1101,7 +1101,7 @@ var DEFAULT_REGEXP = /(\s+|^)default(\s+|$)/;
  *   - `debounce`: integer value which contains the debounce model update value in milliseconds. A
  *     value of 0 triggers an immediate update. If an object is supplied instead, you can specify a
  *     custom value for each event. For example:
- *     `ng-model-options="{ updateOn: 'default blur', debounce: {'default': 500, 'blur': 0} }"`
+ *     `ng-model-options="{ updateOn: 'default blur', debounce: { 'default': 500, 'blur': 0 } }"`
  *   - `allowInvalid`: boolean value which indicates that the model can be set with values that did
  *     not validate correctly instead of the default behavior of setting the model to undefined.
  *   - `getterSetter`: boolean value which determines whether or not to treat functions bound to