Revert "Doc: /_reindex: Add a note about the source size parameter"

This reverts commit 4de284866875b987110df66229fb7c7d0b9cd4d8.

docs/reference/docs/reindex.asciidoc

@@ -131,23 +131,6 @@ POST _reindex
 // CONSOLE
 // TEST[setup:twitter]
 
-You can increase the default batch size by setting the `size` parameter (which defaults to `1000`) to the `source`. Note that it is different than the `size` parameter available at the root, which limits the number of documents (see below).
-
-[source,js]
---------------------------------------------------
-POST /_reindex
-{
-  "source": {
-    "index": "twitter",
-    "size": 2000
-  },
-  "dest": {
-    "index": "new_twitter"
-  }
-}
---------------------------------------------------
-// AUTOSENSE
-
 You can limit the documents by adding a type to the `source` or by adding a
 query. This will only copy ++tweet++'s made by `kimchy` into `new_twitter`: