docs(ngModelController): clarify parse errors

Closes #9952

src/ng/directive/input.js

@@ -1511,12 +1511,17 @@ var VALID_CLASS = 'ng-valid',
  * @property {string} $viewValue Actual string value in the view.
  * @property {*} $modelValue The value in the model that the control is bound to.
  * @property {Array.<Function>} $parsers Array of functions to execute, as a pipeline, whenever
-       the control reads value from the DOM. The functions are called in array order, each passing the value
-       through to the next. The last return value is forwarded to the $validators collection.
-       Used to sanitize / convert the value.
-       Returning undefined from a parser means a parse error occurred. No $validators will
-       run and the 'ngModel' will not be updated until the parse error is resolved. The parse error is stored
-       in 'ngModel.$error.parse'.
+       the control reads value from the DOM. The functions are called in array order, each passing
+       its return value through to the next. The last return value is forwarded to the
+       {@link ngModel.NgModelController#$validators `$validators`} collection.
+
+Parsers are used to sanitize / convert the {@link ngModel.NgModelController#$viewValue
+`$viewValue`}.
+
+Returning `undefined` from a parser means a parse error occurred. In that case,
+no {@link ngModel.NgModelController#$validators `$validators`} will run and the `ngModel`
+will be set to `undefined` unless {@link ngModelOptions `ngModelOptions.allowInvalid`}
+is set to `true`. The parse error is stored in `ngModel.$error.parse`.
 
  *
  * @property {Array.<Function>} $formatters Array of functions to execute, as a pipeline, whenever