unwanted space with `@url`

[2051fde55ac67d92c0532c0483a657aef092b6cb]


Consider the following input.

```
\input texinfo

@top Top

(@uref{https://foo.bar/baz.html,
       baz})

(@uref{https://foo.bar/baz.html, baz})

@bye
```

If I process this with `texi2any --html`, I get the following in the
output

```
<p>(<a class="uref" href="https://foo.bar/baz.html">       baz</a>)
</p>
<p>(<a class="uref" href="https://foo.bar/baz.html">baz</a>)
</p>
```

Why is there a difference in whitespace handling?  This smells like a
bug.


    Werner