fix link in menu docs (#4800)

Author: yihuiliao

packages/@react-spectrum/menu/docs/Menu.mdx

@@ -35,7 +35,7 @@ keywords: [menu trigger, dropdown, action menu]
   packageData={packageData}
   componentNames={['Menu', 'MenuTrigger']}
   sourceData={[
-    {type: 'Spectrum', url: 'https://spectrum.adobe.com/page/popover/'}
+    {type: 'Spectrum', url: 'https://spectrum.adobe.com/page/menu/'}
   ]}
   since="3.0.0" />