Fix redirect for doc section

support-policy section was renamed in
- https://review.opendev.org/#/c/725446/

but redirect for that was not correct. Fixing that
redirect.

Change-Id: Ia2921533c7a61bab4325a4a89b2b84f391e0aafd
diff --git a/doc/source/_extra/.htaccess b/doc/source/_extra/.htaccess
index 1296642..5422af7 100644
--- a/doc/source/_extra/.htaccess
+++ b/doc/source/_extra/.htaccess
@@ -1,4 +1,4 @@
 redirectmatch 301 ^/developer/tempest/(.*) /tempest/latest/$1
 redirectmatch 301 ^/tempest/latest/plugin.html /tempest/latest/plugins/plugin.html
 redirectmatch 301 ^/tempest/latest/plugin-registry.html /tempest/latest/plugins/plugin-registry
-redirectmatch 301 ^/tempest/latest/support-policy /tempest/latest/stable-branch-support-policy
+redirectmatch 301 ^/tempest/latest/#support-policy /tempest/latest/#stable-branch-support-policy