fix(docs): update size example for toolbar

Author: tylermorrisford

packages/nimbus/src/components/toolbar/toolbar.dev.mdx

@@ -52,13 +52,13 @@ const App = () => (
     <Box>
       <Text textStyle="sm" mb="200" color="neutral.11">Size: md</Text>
       <Toolbar size="md">
-        <IconButton size="xs" variant="ghost" aria-label="New">
+        <IconButton size="md" variant="ghost" aria-label="New">
           <Icons.Add />
         </IconButton>
-        <IconButton size="xs" variant="ghost" aria-label="Save">
+        <IconButton size="md" variant="ghost" aria-label="Save">
           <Icons.Save />
         </IconButton>
-        <IconButton size="xs" variant="ghost" aria-label="Print">
+        <IconButton size="md" variant="ghost" aria-label="Print">
           <Icons.Print />
         </IconButton>
       </Toolbar>