chore(date-time-editor): add API docs for input type requirement

Author: MonikaKirkova

projects/igniteui-angular/src/lib/directives/date-time-editor/date-time-editor.directive.ts

@@ -36,6 +36,10 @@ import { DateTimeUtil } from '../../date-common/util/date-time.util';
  * Supports display format that may differ from the input format.
  * Provides methods to increment and decrement any specific/targeted `DatePart`.
  *
+ * **Note:** This directive uses the Mask Directive internally and requires `type="text"` on the input element.
+ * Input elements with `type="date"` or other date/time types are not supported, as they do not allow
+ * programmatic cursor positioning and text selection required for mask functionality.
+ *
  * @example
  * ```html
  * <igx-input-group>