chore: Updating final Store docs for v3

markdown/dev/reference/api/store/unset/en.md

@@ -0,0 +1,21 @@
+---
+title: Store.unset()
+---
+
+The `Store.unset()` value removes a `key` from the store.
+
+## Signature
+
+```js
+Store store.unset(string key)
+```
+
+<Tip compact>This method is chainable as it returns the `Store` object</Tip>
+
+## Example
+
+```js
+const store = new Store()
+  .set('example', 'I will be gone before you know it')
+  .unset('example')
+```