change test to test whether the underlying dom tag is changed to span when using as prop (#2283)

Test in line 105 already covers using the as tag to change the underlying dom tag to an anchor tag. Therefore we can test whether a span tag is correctly rendered for example.

packages/@headlessui-react/src/components/transitions/transition.test.tsx

@@ -127,15 +127,15 @@ describe('Setup API', () => {
 
     it('should be possible to change the underlying DOM tag', () => {
       let { container } = render(
-        <Transition show={true} as="a">
+        <Transition show={true} as="span">
           Children
         </Transition>
       )
 
       expect(container.firstChild).toMatchInlineSnapshot(`
-        <a>
+        <span>
           Children
-        </a>
+        </span>
       `)
     })