doc: update URL for sparse's tarballs

The URL given to get sparse's tarballs is sparse.wiki.kernel.org
but the wiki will is deprecated in favor of sparse.docs.kernel.org.

So, update this URL to the one where the tarballs can directly
be found.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Link: https://lore.kernel.org/r/20200621153330.54480-1-luc.vanoostenryck@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/dev-tools/sparse.rst

@@ -73,8 +73,8 @@ sparse would otherwise report a context imbalance.
 Getting sparse
 --------------
 
-You can get latest released versions from the Sparse homepage at
-https://sparse.wiki.kernel.org/index.php/Main_Page
+You can get tarballs of the latest released versions from:
+https://www.kernel.org/pub/software/devel/sparse/dist/
 
 Alternatively, you can get snapshots of the latest development version
 of sparse using git to clone::