[DOCS] Add type parms with warnings

Author: jrodewig

docs/reference/docs/reindex.asciidoc

@@ -484,6 +484,18 @@ Use in conjunction with `max_docs` to control what documents are reindexed.
 Set to a list to reindex select fields. 
 Defaults to `true`. 
 
+`type`:::
+(Optional, string)
+deprecated:[6.0.0,Types are deprecated and in the process of being removed. See <<removal-of-types>>.]
+<<mapping-type-field,Document type>> to reindex.
++
+[WARNING]
+====
+By default, all reindexed documents are assigned the `_doc` document type. To
+preserve other document types during a reindex, specify the `type` in the `dest`
+index.
+====
+
 `dest`::
 `index`:::
 (Required, string) The name of the index you are copying _to_.
@@ -497,9 +509,22 @@ See <<index-version-types>> for more information.
 (Optional, enum) Set to create to only index documents that do not already exist (put if absent). 
 Valid values: `index`, `create`. Defaults to `index`.
 
+`type`:::
+(Optional, string)
+deprecated:[6.0.0,Types are deprecated and in the process of being removed. See <<removal-of-types>>.]
+<<mapping-type-field,Document type>> for reindexed documents.
+Defaults to `_doc`.
++
+[WARNING]
+====
+By default, all reindexed documents are assigned the `_doc` document type.
+To preserve other document types, this parameter must be specified.
+====
+
 `script`::
 `source`::: 
 (Optional, string) The script to run to update the document source or metadata when reindexing. 
+
 `lang`:::
 (Optional, enum) The script language: `painless`, `expression`, `mustache`, `java`. 
 For more information, see <<modules-scripting>>.