Add config options page.nextPrevSortOrder/nextPrevInSectionSortOrder

See #12776

data/docs.yaml

@@ -1600,6 +1600,9 @@ config:
     term:
     - html
     - rss
+  page:
+    nextPrevInSectionSortOrder: desc
+    nextPrevSortOrder: desc
   paginate: 0
   paginatePath: ""
   pagination:
@@ -1784,6 +1787,8 @@ config_helpers:
       _merge: shallow
     outputs:
       _merge: none
+    page:
+      _merge: none
     pagination:
       _merge: none
     params: