docs: Update download location for Go packages

We haven't ever made releases of the Go components, which makes
sense because that's just not how that specific ecosystem works.

For people who are looking to use libvirt from Go, the brief
introductory pages located at the same URLs used to import the
packages are a better entry point than an empty directory
listing, so let's send them there instead.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

docs/downloads.html.in

@@ -61,7 +61,7 @@
         <tr>
           <td>Go</td>
           <td>
-            <a href="https://libvirt.org/sources/go/">libvirt</a>
+            <a href="https://libvirt.org/libvirt-go">libvirt</a>
           </td>
           <td>
             <a href="https://libvirt.org/git/?p=libvirt-go.git;a=summary">libvirt</a>
@@ -196,7 +196,7 @@
         <tr>
           <td>Go XML</td>
           <td>
-            <a href="https://libvirt.org/sources/go/">libvirt</a>
+            <a href="https://libvirt.org/libvirt-go-xml">libvirt</a>
           </td>
           <td>
             <a href="https://libvirt.org/git/?p=libvirt-go-xml.git;a=summary">libvirt</a>