docs(ngModel): fix typo and rephrase for simplicity

Author: gkalpak

src/ng/directive/ngModel.js

@@ -446,12 +446,12 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
    *
    * @description
    * Cancel an update and reset the input element's value to prevent an update to the `$modelValue`,
-   * which may be caused by a pending debounced event or because the input is waiting for a some
+   * which may be caused by a pending debounced event or because the input is waiting for some
    * future event.
    *
    * If you have an input that uses `ng-model-options` to set up debounced updates or updates that
-   * depend on special events such as blur, you can have a situation where there is a period when
-   * the `$viewValue` is out of sync with the ngModel's `$modelValue`.
+   * depend on special events such as `blur`, there can be a period when the `$viewValue` is out of
+   * sync with the ngModel's `$modelValue`.
    *
    * In this case, you can use `$rollbackViewValue()` to manually cancel the debounced / future update
    * and reset the input to the last committed view value.