chore: add brief explanation of hasFeedbackFor and showsFeedbackFor (#720)

packages/validate/stories/Overview.stories.mdx

@@ -22,6 +22,25 @@ not always lead to the desired User Experience.
 Together with [interaction states](?path=/docs/forms-system-interaction-states--interaction-states),
 validity states can determine whether a validation message should be shown along the input field.
 
+## Assessing field validation state programmatically
+When a field has validation feedback it can be accessed using the `hasFeedbackFor` and `showsFeedbackFor` properties.
+This can be used if the validity of the field is needed in code.
+
+`hasFeedbackFor` is the state of the field regardless of whether the feedback is shown or not.
+`showsFeedbackFor` represents whether or not validation feedback is being shown. This takes into account 
+interaction state such as a field being `touched` and `dirty`, `prefilled` or `submitted`
+
+```js
+// Field is invalid and has not interacted with
+const field = document.querySelector('#my-field');
+field.hasFeedbackFor.includes('error') // returns true
+field.showsFeedbackFor.includes('error') // returns false
+
+// Field  invalid, dirty and touched
+field.hasFeedbackFor.includes('error') // returns true
+field.showsFeedbackFor.includes('error') // returns true
+```
+
 ## Validators
 
 All validators are extensions of the `Validator` class. They should be applied to the element implementing