fix(types): typo of `vOnce` and `vSlot` (#13343)

packages/runtime-dom/src/index.ts

@@ -58,8 +58,8 @@ declare module '@vue/runtime-core' {
     vOn: VOnDirective
     vBind: VModelDirective
     vIf: Directive<any, boolean>
-    VOnce: Directive
-    VSlot: Directive
+    vOnce: Directive
+    vSlot: Directive
   }
 }