Organize hooks documentation and add subheadings

docs/libraries/slate-react/hooks.md

@@ -1,36 +1,46 @@
 # Slate React Hooks
 
+- [Check hooks](hooks.md#check-hooks)
+- [Editor hooks](hooks.md#editor-hooks)
+- [Selection hooks](hooks.md#selection-hooks)
+
+### Check hooks
+
 React hooks for Slate editors
 
-### `useFocused(): boolean`
+#### `useFocused(): boolean`
 
 Get the current `focused` state of the editor.
 
-### `useReadOnly(): boolean`
+#### `useReadOnly(): boolean`
 
 Get the current `readOnly` state of the editor.
 
-### `useSelected(): boolean`
+#### `useSelected(): boolean`
 
 Get the current `selected` state of an element.
 
-### `useSlate(): ReactEditor`
+### Editor hooks
+
+#### `useSlate(): ReactEditor`
 
 Get the current editor object from the React context. Re-renders the context whenever changes occur in the editor.
 
-### `useSlateWithV(): { editor: ReactEditor, v: number }`
+#### `useSlateWithV(): { editor: ReactEditor, v: number }`
 
 The same as `useSlate()` but includes a version counter which you can use to prevent re-renders.
 
-### `useSlateStatic(): ReactEditor`
+#### `useSlateStatic(): ReactEditor`
 
 Get the current editor object from the React context. A version of useSlate that does not re-render the context. Previously called `useEditor`.
 
-### `useSlateSelection(): (BaseRange & { placeholder?: string | undefined; onPlaceholderResize?: ((node: HTMLElement | null) => void) | undefined }) | null`
+### Selection hooks
+
+#### `useSlateSelection(): (BaseRange & { placeholder?: string | undefined; onPlaceholderResize?: ((node: HTMLElement | null) => void) | undefined }) | null`
 
 Get the current editor selection from the React context. Only re-renders when the selection changes.
 
-### `useSlateSelector<T>(selector: (editor: Editor): T, equalityFn?: (a: T, b: T) => boolean): T`
+#### `useSlateSelector<T>(selector: (editor: Editor): T, equalityFn?: (a: T, b: T) => boolean): T`
 
 Similar to `useSlateSelection` but uses redux style selectors to prevent rerendering on every keystroke.