[DOCS] Fix broken 2.4 links to Elasticsearch Reference Guide

Author: jrodewig

010_Intro/10_Installing_ES.asciidoc

@@ -12,7 +12,7 @@ You can get the latest version of Elasticsearch from
 https://www.elastic.co/downloads/elasticsearch[_elastic.co/downloads/elasticsearch_].
 
 To install Elasticsearch, download and extract the archive file for your platform. For
-more information, see the {ref}/install-elasticsearch.html[Installation] topic
+more information, see the https://www.elastic.co/guide/en/elasticsearch/reference/5.6/install-elasticsearch.html[Installation] topic
 in the Elasticsearch Reference.
 
 [TIP]

170_Relevance/65_Script_score.asciidoc

@@ -115,7 +115,7 @@ scripts are not quite fast enough, you have three options:
   document.
 * Groovy is fast, but not quite as fast as Java.((("Java", "scripting in")))  You could reimplement your
   script as a native Java script. (See
-  {ref}/modules-scripting-native.html[Native Java Scripts]).
+  https://www.elastic.co/guide/en/elasticsearch/reference/5.6/modules-scripting-native.html[Native Java Scripts]).
 * Use the `rescore` functionality((("rescoring"))) described in <<rescore-api>> to apply
   your script to only the best-scoring documents.
 

410_Scaling/80_Scale_is_not_infinite.asciidoc

@@ -83,5 +83,5 @@ small and agile.
 Eventually, despite your best intentions, you may find that the number of
 nodes and indices and mappings that you have is just too much for one cluster.
 At this stage, it is probably worth dividing the problem into multiple
-clusters.  Thanks to {ref}/modules-cross-cluster-search.html[cross cluster search], you can even run
+clusters.  Thanks to https://www.elastic.co/guide/en/elasticsearch/reference/5.6/modules-cross-cluster-search.html[cross cluster search], you can even run
 searches across multiple clusters, as if they were one big cluster.