docs: update

Author: hunterliu1003

docs/content/2.get-started/1.guide/4.types.md

@@ -20,22 +20,28 @@ export type ModalId = number | string | symbol
 export type StyleValue = string | CSSProperties | (string | CSSProperties)[]
 ```
 
+## ModalSlot
+
+```ts
+export type ModalSlot<T extends Record<string, any> = {}> = string | Component | {
+  component: Component
+  attrs?: T
+}
+```
+
 ## UseModalOptionsPrivate
 
 ```ts
 export type UseModalOptionsPrivate<
-  ModalProps extends ComponentProps,
-  DefaultSlotProps extends ComponentProps,
+  ModalProps extends ComponentProps = {},
+  DefaultSlotProps extends ComponentProps = {},
 > = {
   context?: Vfm
   component: Component
   attrs?: ModalProps
   slots?: {
-    default: string | {
-      component: Component
-      attrs?: DefaultSlotProps
-    }
-    [key: string]: any
+    default: ModalSlot<DefaultSlotProps>
+    [key: string]: ModalSlot
   }
 
   id?: symbol