Update the htaccess.ref-guide-antora for release 9.9.0
diff --git a/themes/solr/templates/htaccess.ref-guide-antora b/themes/solr/templates/htaccess.ref-guide-antora
index 173ae9e..134866a 100644
--- a/themes/solr/templates/htaccess.ref-guide-antora
+++ b/themes/solr/templates/htaccess.ref-guide-antora
@@ -1,2 +1,2 @@
-Redirect 302 /guide/solr/9_8 /guide/solr/latest
+Redirect 302 /guide/solr/9_9 /guide/solr/latest
 Redirect 301 /guide/index.html /guide/solr/latest/index.html