add createStore to /reference (#694)

Author: atilafassina

src/routes/reference/store-utilities/create-store.mdx

@@ -0,0 +1,88 @@
+---
+title: createStore
+---
+
+Stores were intentionally designed to manage data structures like objects and arrays but are capable of handling other data types, such as strings and numbers.
+
+## Types Signature
+
+```tsx
+import { createStore } from "solid-js/store";
+import type { StoreNode, Store, SetStoreFunction } from "solid-js/store";
+
+function createStore<T extends StoreNode>(
+	state: T | Store<T>
+): [get: Store<T>, set: SetStoreFunction<T>];
+
+type Store<T> = T; // conceptually readonly, but not typed as such
+```
+
+## Usage
+
+```tsx
+import { createStore } from "solid-js/store";
+
+// Initialize store
+const [store, setStore] = createStore({
+	userCount: 3,
+	users: [
+		{
+			id: 0,
+			username: "felix909",
+			location: "England",
+			loggedIn: false,
+		},
+		{
+			id: 1,
+			username: "tracy634",
+			location: "Canada",
+			loggedIn: true,
+		},
+		{
+			id: 1,
+			username: "johny123",
+			location: "India",
+			loggedIn: true,
+		},
+	],
+});
+```
+
+## Getter
+
+Store objects support the use of getters to store derived values.
+
+```tsx
+const [state, setState] = createStore({
+	user: {
+		firstName: "John",
+		lastName: "Smith",
+		get fullName() {
+			return `${this.firstName} ${this.lastName}`;
+		},
+	},
+});
+```
+
+## Setter
+
+Changes can take the form of function that passes previous state and returns new state or a value.
+Objects are always shallowly merged. Set values to undefined to delete them from the Store.
+In TypeScript, you can delete a value by using a non-null assertion, like `undefined!`.
+
+```tsx
+const [state, setState] = createStore({
+	firstName: "John",
+	lastName: "Miller",
+});
+
+setState({ firstName: "Johnny", middleName: "Lee" });
+// ({ firstName: 'Johnny', middleName: 'Lee', lastName: 'Miller' })
+
+setState((state) => ({ preferredName: state.firstName, lastName: "Milner" }));
+// ({ firstName: 'Johnny', preferredName: 'Johnny', middleName: 'Lee', lastName: 'Milner' })
+```
+
+---
+
+To learn more about using stores check the [Stores Guide](/concepts/stores), and the **Store Utilities** section for more advanced APIs.

src/routes/reference/store-utilities/data.json

@@ -1,6 +1,7 @@
 {
 	"title": "Store Utilities",
 	"pages": [
+		"create-store.mdx",
 		"produce.mdx",
 		"reconcile.mdx",
 		"unwrap.mdx",