[DOCS] Added documentation for CAT Aliases API

Added asciidoc. Added new lines in java class.

docs/reference/cat.asciidoc

@@ -94,6 +94,8 @@ green foo   1 0   227   0   2065131   2065131
 
 --
 
+include::cat/alias.asciidoc[]
+
 include::cat/allocation.asciidoc[]
 
 include::cat/count.asciidoc[]

docs/reference/cat/alias.asciidoc

@@ -0,0 +1,22 @@
+[[cat-alias]]
+== Aliases
+
+`aliases` shows information about currently configured aliases to indices
+including filter and routing infos.
+
+[source,shell]
+--------------------------------------------------
+% curl '192.168.56.10:9200/_cat/aliases?v'
+alias  index filter indexRouting searchRouting
+alias2 test1 *      -            -
+alias4 test1 -      2            1,2
+alias1 test1 -      -            -
+alias3 test1 -      1            1
+--------------------------------------------------
+
+The output shows that `alias` has configured a filter, and specific routing
+configurations in `alias3` and `alias4`. 
+
+If you only want to get information about a single alias, you can specify
+the alias in the URL, for example `/_cat/aliases/alias1`.
+

src/main/java/org/elasticsearch/rest/action/cat/RestAliasAction.java

@@ -82,8 +82,8 @@ public class RestAliasAction extends AbstractCatAction {
 
     @Override
     void documentation(StringBuilder sb) {
-        sb.append("/_cat/aliases");
-        sb.append("/_cat/aliases/{alias}");
+        sb.append("/_cat/aliases\n");
+        sb.append("/_cat/aliases/{alias}\n");
     }
 
     @Override
@@ -93,8 +93,8 @@ public class RestAliasAction extends AbstractCatAction {
         table.addCell("alias", "desc:alias name");
         table.addCell("index", "desc:index alias points to");
         table.addCell("filter", "desc:filter");
-        table.addCell("index_routing", "desc:index routing");
-        table.addCell("search_routing", "desc:search routing");
+        table.addCell("indexRouting", "desc:index routing");
+        table.addCell("searchRouting", "desc:search routing");
         table.endHeaders();
         return table;
     }