chore: Port FreeSewing.dev to docusaurus

The replaces the NextJS site powering FreeSewing.dev with a Docusaurus
setup. It's part of my efforts to simplify FreeSewing's setup so we can
focus on our core value proposition.

sites/dev/docs/reference/api/store/unset/readme.mdx

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